[Numpy-discussion] Adding an axis argument to numpy.unique

josef.pktd@gmai... josef.pktd@gmai...
Tue Aug 20 06:47:53 CDT 2013


On Tue, Aug 20, 2013 at 7:34 AM, Nathaniel Smith <njs@pobox.com> wrote:
> On 20 Aug 2013 12:09, <josef.pktd@gmail.com> wrote:
>>
>> On Tue, Aug 20, 2013 at 5:04 AM, Nathaniel Smith <njs@pobox.com> wrote:
>> > On 20 Aug 2013 01:39, "Joe Kington" <joferkington@gmail.com> wrote:
>> >>
>> >>
>> >>
>> >>
>> >> ...<snip>
>> >>>
>> >>>
>> >>> However, my first interpretation of an axis argument in unique would
>> >>> be that it treats each column (or whatever along axis) separately.
>> >>> Analogously to max, argmax and similar.
>> >>
>> >>
>> >> Good point!
>> >>
>> >> That's certainly a potential source of confusion.  However, I can't
>> >> seem
>> >> to come up with a better name for the kwarg. Matlab's "unique" function
>> >> has
>> >> a "rows" option, which is probably a more intuitive name, but doesn't
>> >> imply
>> >> the expansion to N-dimensions.
>> >>
>> >> "axis" is still fairly idiomatic, despite the confusion over "unique
>> >> rows/columns/etc" vs "unique items within each row/column/etc".
>> >>
>> >> Any thoughts on a better name for the argument?
>> >
>> > I also found this pretty confusing when first looking at the PR.
>> >
>> > One option might be to invert the sense of the argument to emphasize
>> > that
>> > it's treating subarrays as units, so instead of specifying the iteration
>> > axis you specify the axes of the subarray. compare_axis= or something?
>>
>> you would need compare_axes (plural for ndim>2) and have to specify
>> all but one axis, AFAICS.
>
> Well, it makes sense to specify any arbitrary subset of axes, whether or not
> that's currently implemented.

not AFAICS, if you want to return a rectangular array without
nans/missing values.

Josef

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