[Python-ideas] slice[] to get more complex slices

[Stefan Behnel]

Stephan Hoyer schrieb am 23.07.2018 um 18:01:
> On Mon, Jul 23, 2018 at 4:24 AM Paul Moore wrote:
> 
>> I thought the reason the proposal got nowhere was because it's pretty
>> simple to define it yourself:
>>
>> >>> class SliceHelper:
>> ...     def __getitem__(self, slice):
>> ...         return slice
>> ...
>> >>> SH = SliceHelper()
>> >>> SH[1::3]
>> slice(1, None, 3)
>>
>> Did I miss something significant about why this wasn't sufficient?
> 
> 
> I think a SliceHelper class like this is a reasonable solution, but there
> would be a lot of value having it a standard place somewhere in the
> standard library (e.g., operator.subscript).
> 
> Both pandas and NumPy include this helper object under different names
> (pandas.IndexSlice and numpy.index_exp / numpy.s_), but it would be
> surprising/unexpected for pandas/numpy specific helpers to show up when not
> using one of those libraries. I do the exact same sorts of indexing
> manipulations with xarray, dask and TensorFlow.
> 
> Given that this is basically a simple feature to make it easier to work
> with Python syntax (so there's no danger it will change in the future), I
> think there is a lot to be said for putting it in the standard library in
> one place so it's obvious what to use and users don't have to relearn that
> name for this object and/or reimplement it.

Please copy that comment into the ticket and ask for it to be reopened.

https://bugs.python.org/issue24379

Stefan