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From: etgil on 17 May 2010 10:07 2 vectors x=[a b c a b c a b c a b c....] y=unique(x).... so (a b c). trying to index x so that i have a matrix that would look something like this. the resulting matrix is of size numel(x) by numel(y) a b c 0 1 0 0 1 0 0 0 1 1 0 0
From: Walter Roberson on 17 May 2010 14:58 etgil wrote: > 2 vectors > x=[a b c a b c a b c a b c....] > y=unique(x).... so (a b c). > > trying to index x so that i have a matrix that would look something like this. the resulting matrix is of size numel(x) by numel(y) > > a b c > 0 1 0 > 0 1 0 > 0 0 1 > 1 0 0 [y,I,J] = unique(x); T = zeros(length(J),length(y), 'logical'); T(sub2ind(size(T), 1:length(J), J)) = true;
From: Nathan on 17 May 2010 15:02 On May 17, 11:07 am, etgil <etienne.giroux.levei...(a)gmail.com> wrote: > 2 vectors > x=[a b c a b c a b c a b c....] > y=unique(x).... so (a b c). > > trying to index x so that i have a matrix that would look something like this. the resulting matrix is of size numel(x) by numel(y) > > a b c > 0 1 0 > 0 1 0 > 0 0 1 > 1 0 0 What exactly are you trying to do? I can't make sense of what you just posted. Apparently, from the subject line, you want to do something without loops. You want to create some matrix of size numel(x) by numel(y). The sample matrix that you provided doesn't make sense. Already, the matrix is not of size numel(x) by numel(y), as numel(x) is at least 12 (not including the dots), while the dimensions of the provided matrix are 5x3 (including the a b c)... Can you give an actual example of what you are trying to do with some sample data instead of these mysterious variables/values of "a" "b" and "c"? -Nathan
From: etgil on 17 May 2010 12:32 Thanks, This is very close to what I need. It doesn't seem to handle the 'logical' part very well.
From: Walter Roberson on 17 May 2010 16:49
etgil wrote: > This is very close to what I need. > > It doesn't seem to handle the 'logical' part very well. That part isn't important. You can leave out the 'logical' in the zeros() call, and change the true to 1. The only difference will be in the amount of storage used, and whether you can directly use the result as a logical index or not. |