[Numpy-discussion] np.equal
Michael Droettboom
mdroe at stsci.edu
Mon Dec 7 09:06:00 EST 2009
There was some discussion on this recently. "==" actually has special
fall-back code for strings, whereas "equal" is just a "raw" ufunc, and
no ufunc's support strings.
http://www.mail-archive.com/numpy-discussion@scipy.org/msg21408.html
Of course bool(NotImplemented) == True is sort of a separate issue that
can be dealt with independently of whether ufuncs grow string support of
not.
Mike
Pauli Virtanen wrote:
> su, 2009-12-06 kello 23:01 -0800, Fernando Perez kirjoitti:
>
>> 2009/12/6 josef.pktd <josef.pktd at gmail.com>:
>>
>>>>>> np.equal(np.arange(5),'a')
>>>>>>
>>> NotImplemented
>>>
>> Why is NotImplemented a *return* value? Normally NotImplementedError
>> is a raised exception, but if it's not implemented, it shouldn't be
>> returned as a value.
>>
>
> Maybe it is so because some code paths are shared with the == operation?
>
> But in any case, NotImplemented should never be returned to the user --
> I believe it's only meant to be an internal value used in determining
> the proper comparison operation between values.
>
> A bug ticket should be filed for this, I believe.
>
>
--
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA
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