[Python-ideas] Changing the meaning of bool.__invert__

[Oscar Benjamin]

On 7 April 2016 at 14:08, Robert Kern <robert.kern at gmail.com> wrote:
>> This is a consequence of another unfortunate design by numpy. The
>> reason for this is that numpy uses Python's bitwise operators to do
>> element-wise logical operations.
>
>
> This is not correct. & | ^ ~ are all genuine bitwise operations on numpy
> arrays.
>
>>>> i = np.arange(5)
>>>> ~i
> array([-1, -2, -3, -4, -5])
>
> What you are seeing with bool arrays is that bool arrays are *not* just
> uint8 arrays. Each element happens to take up a single 8-bit byte, but only
> one of those bits contributes to its value; the other 7 bits are mere
> padding. The bitwise & | ^ ~ operators all work on that single bit
> correctly. They do not operate on the padding bits as they are not part of
> the bool's value.

I stand corrected.

--
Oscar