[Numpy-discussion] Should bool_ subclass int?

Alan G Isaac aisaac at american.edu
Tue Jul 10 11:31:35 EDT 2007

Hi Gael,

More important is the following.

On Tue, 10 Jul 2007, Alan G Isaac apparently wrote: 
>>>> N.array([False])-N.array([True]) 
> array([True], dtype=bool) 
>>>> N.array([False])+(-N.array([True])) 
> array([False], dtype=bool) 

> The second answer is the right one, in this context.  
> I would call this [first!!!] answer a bug. 

Do you agree that the first (!!!) answer is a bug?
(The basis is apparently performed as follows:
integer array subtraction is first performed, and
then nonzero ints are converted to True.  But this
gives the wrong answer and most critically breaks
the equivalence of a-b and a+(-b).)


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