[Numpy-discussion] possible enhancement to getitem?

Neal Becker ndbecker2@gmail....
Fri Jun 8 08:14:55 CDT 2012


Robert Kern wrote:

> On Thu, Jun 7, 2012 at 7:55 PM, Neal Becker <ndbecker2@gmail.com> wrote:
>> In [3]: u = np.arange(10)
>>
>> In [4]: u
>> Out[4]: array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>
>> In [5]: u[-2:]
>> Out[5]: array([8, 9])
>>
>> In [6]: u[-2:2]
>> Out[6]: array([], dtype=int64)
>>
>> I would argue for consistency it would be desirable for this to return
>>
>> [8, 9, 0, 1]
> 
> Unfortunately, this would be inconsistent with Python semantics:
> 
> [~]
> |1> u = range(10)
> 
> [~]
> |2> u[-2:2]
> []
> 

The fact that this proposed numpy behavior would not match python list behavior 
holds little weight for me.  I would still favor this change, unless it added 
significant overhead.  My opinion, of course.



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