numpy-discussion

[Numpy-discussion] putmask/take ?

[P G. <pgm...@gm...>]

Folks,
I'm running into the following problem with putmask on take.

>>> import numpy
>>> x = N.arange(12.)
>>> m = [1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1]
>>> i = N.nonzero(m)[0]
>>> w = N.array([-1, -2, -3, -4.])
>>> x.putmask(w,m)
>>> x.take(i)
>>> N.allclose(x.take(i),w)
False


I'm wondering ifit is intentional, or if it's a problem on my build (1.0b5),
 or if somebody experiences that as well.
Thanks a lot for your input.

P.

Re: [Numpy-discussion] putmask/take ?

[Stefan v. d. W. <st...@su...>]

On Thu, Sep 21, 2006 at 08:35:02PM -0400, P GM wrote:
> Folks,
> I'm running into the following problem with putmask on take.
>=20
> >>> import numpy
> >>> x =3D N.arange(12.)
> >>> m =3D [1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1]
> >>> i =3D N.nonzero (m)[0]
> >>> w =3D N.array([-1, -2, -3, -4.])
> >>> x.putmask(w,m)

You can also use N.place:

    Similar to putmask arr[mask] =3D vals but the 1D array vals has the
    same number of elements as the non-zero values of mask. Inverse of
    extract.

> >>> x.take(i)
> >>> N.allclose(x.take(i),w)
> False

Regards
St=E9fan

Re: [Numpy-discussion] putmask/take ?

[PGM <pgm...@gm...>]

Stefan,
Thanks for your suggestions, but that won't do for what I'm working on : I 
need to get putmask working, or at least knowing it doesnt'.

Robert, thanks for your input. The function putmask doesn't work either.
Oh, thinking about it: would it be possible to have the same order of 
arguments in the function and the method ? Compare

putmask(array, mask, values) with array.putmask(values, mask)

The same comment applies to put:
put(array, indices, values) vs array.put(values, indices, mode)

That's a tad confusing...