[Numpy-discussion] Help w/ indexing, please

John Salvatier jsalvati@u.washington....
Tue Jul 27 11:32:05 CDT 2010

I am pretty sure you should be able to do

R = C[L, :]  and get the array you want.

Try it with a small matrix where  you know the result you want. You may need
to transpose some axes afterwards, but I don't think you should.

On Tue, Jul 27, 2010 at 9:10 AM, David Goldsmith <d.l.goldsmith@gmail.com>wrote:

> Hi!  I have a large M x K, M, K ~ 1e3 array L of indices - non-negative
> integers in the range 0 to N-1 - and an N x 3 array C (a matplotlib
> colormap).  I need to create an M x K x 3 array R such that R[m,k,j] =
> C[L[m,k], j], j = 0,1,2.  I want to do so w/out having to loop through all
> the (m,k) index pairs, but I'm having trouble wrapping my brain around how
> to do it - please help.  Thanks.
> DG
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