Re: [Numpy-discussion] addressing a submatrix

[Karol L. <kar...@kn...>]

On Wednesday 14 June 2006 11:14, Martin Wiechert wrote:
> is there a concise way to address a subrectangle of a 2d array? So far I'm
> using
>
> A [I] [:, J]
>
> which is not pretty and more importantly only works for reading the
> subrectangle. Writing does *not* work. (Cf. session below.)
>
> Any help would be appreciated.
>
> Thanks,
> Martin

You can also use A[m:n,r:s] to refernce a subarray.

=46or instance:
>>> a =3D numpy.zeros((5,5))
>>> b =3D numpy.ones((3,3))
>>> a[1:4,1:4] =3D b
>>> a
array([[0, 0, 0, 0, 0],
       [0, 1, 1, 1, 0],
       [0, 1, 1, 1, 0],
       [0, 1, 1, 1, 0],
       [0, 0, 0, 0, 0]])

Cheers,
Karol

=2D-=20
written by Karol Langner
=B6ro cze 14 11:49:35 CEST 2006