[Numpy-discussion] nonzero() behaviour has changed

[Ed Schofield]

Bill Baxter wrote:
> Aren't there quite a few functions that return indices like nonzero()
> does?
> Should they all have arg*** versions that just transpose the output of
> the non arg*** version?
>
> Maybe the answer is yes, but to me if all it takes to get what you
> needs is transpose() then I'm not sure how that fails to be obvious. 
> You have [[x y z] [p d q]] and you want ([x p][y d][z q]).  Looks like
> a job for transpose! 
> Maybe a note in the docstring pointing out "the obvious" is what is
> really warranted.  As in "hey, look, you can transpose the output of
> this function if you'd like the indices the other way, but the way it
> is it's more useful for indexing, as in a[ a.nonzero()]."

Well, it wasn't immediately obvious to me how it could be done so
elegantly.  But I agree that a new function isn't necessary.  I've
re-written the docstring for the nonzero method in SVN to point out how
to do it.

> Sure would be nice if all you had to type was a.nonzero().T, though... ;-P

No, this wouldn't be possible -- the output of the nonzero method is a
tuple, not an array.  Perhaps this is why it's not _that_ obvious ;)

-- Ed