Hi Simon, thanks for your reply.
A [I, J] seems to only work if the indices are *strides* as in your example. I need fancy indices (like I = (1,3,4), J = (0,3,5)), and for them A [I, J] won't do what I want. As you can see from the example session I posted it does not address the whole rectangle IxJ but only the elements (I_1, J_1), (I_2, J_2). E.g., if I==J this is the diagonal of the submatrix, not the full submatrix. Martin On Wednesday 14 June 2006 20:25, Simon Burton wrote: > On Wed, 14 Jun 2006 11:14:17 +0200 > > Martin Wiechert <[EMAIL PROTECTED]> wrote: > > Hi list, > > > > is there a concise way to address a subrectangle of a 2d array? So far > > I'm using > > > > A [I] [:, J] > > what about A[I,J] ? > > Simon. > > >>> import numpy > >>> a=numpy.zer > > numpy.zeros numpy.zeros_like > > >>> a=numpy.zeros([4,4]) > >>> a > > array([[0, 0, 0, 0], > [0, 0, 0, 0], > [0, 0, 0, 0], > [0, 0, 0, 0]]) > > >>> a[2:3,2:3]=1 > >>> a > > array([[0, 0, 0, 0], > [0, 0, 0, 0], > [0, 0, 1, 0], > [0, 0, 0, 0]]) > > >>> a[1:3,1:3]=1 > >>> a > > array([[0, 0, 0, 0], > [0, 1, 1, 0], > [0, 1, 1, 0], > [0, 0, 0, 0]]) _______________________________________________ Numpy-discussion mailing list Numpy-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/numpy-discussion
