[SciPy-dev] Arrays as truth values?
oliphant at ee.byu.edu
Mon Nov 7 15:54:44 CST 2005
Perry Greenfield wrote:
>Essentially, my argument is that this case presents many likely
>surprises for users and when there isn't one obvious way to do it, it
>shouldn't be done. I'd argue that not allowing arrays as truth values
>it is more Pythonic. (Existing arrays don't support rich comparisons,
>and they are false only when empty, as would be expected).
Right now, I'm leaning towards raising an error. A big explanation for
that is the idea that "explicit" is better than "implicit." I'm
persuaded by Perry's argument that a casual user is going to think that
"and" and "&" have the same behavior for arrays. The experienced user
is going to understand the difference, anyway.
So ultimately, I don't really see an impressive use case for returning a
truth value for arrays, but I do see a "new-user" issue if an error is
So, right now in SVN, arrays as truth values raise erros unless the
array contains only one element (in which case it is unambiguous).
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