Question: I'm trying to write a function in python that is like:

```
def repeated(f, n):
    ...

```

where `f` is a function that takes one argument and `n` is a positive integer.

For example if I defined square as:

```
def square(x):
    return x * x

```

and I called

```
repeated(square, 2)(3)

```

this would square 3, 2 times.

Answer: 
Use an itertools recipe called `repeatfunc` that performs this operation.

**Given**

```
def square(x):
    """Return the square of a value."""
    return x * x

```

**Code**

From [itertools recipes](https://docs.python.org/3/library/itertools.html#itertools-recipes):

```
def repeatfunc(func, times=None, *args):
    """Repeat calls to func with specified arguments.

    Example:  repeatfunc(random.random)
    """
    if times is None:
        return starmap(func, repeat(args))
    return starmap(func, repeat(args, times))

```

**Demo**

Optional: You can use a third-party library, [`more_itertools`](https://github.com/erikrose/more-itertools), that conveniently implements these recipes:

```
import more_itertools as mit

list(mit.repeatfunc(square, 2, 3))
# [9, 9]

```

Install via `> pip install more_itertools`
Using reduce and itertools.repeat (as Marcin suggested):

```
from itertools import repeat
from functools import reduce # necessary for python3

def repeated(func, n):
    def apply(x, f):
        return f(x)
    def ret(x):
        return reduce(apply, repeat(func, n), x)
    return ret

```

You can use it as follows:

```
>>> repeated(os.path.dirname, 3)('/a/b/c/d/e/f')
'/a/b/c'

>>> repeated(square, 5)(3)
1853020188851841

```

(after importing `os` or defining `square` respectively)