Question: `Dataframe.resample()` works only with timeseries data. I cannot find a way of getting every nth row from non-timeseries data. What is the best method?

Answer: 
I'd use `iloc`, which takes a row/column slice, both based on integer position and following normal python syntax. If you want every 5th row:

```
df.iloc[::5, :]

```
I had a similar requirement, but I wanted the n'th item in a particular group. This is how I solved it.

```
groups = data.groupby(['group_key'])
selection = groups['index_col'].apply(lambda x: x % 3 == 0)
subset = data[selection]

```