convert a double array to something like logical

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freebil
freebil on 15 Oct 2013
Answered: hayim on 13 Jan 2014
Hello. I want to concert every
1-> 1 0 0 0 0 0 0
2-> 0 1 0 0 0 0 0
3-> 0 0 1 0 0 0 0
4-> 0 0 0 1 0 0 0
5-> 0 0 0 0 1 0 0
6-> 0 0 0 0 0 1 0
7-> 0 0 0 0 0 0 1
example: I have a vector A=[1;5;7;4]; I want it to be S= [
1 0 0 0 0 0 0
0 0 0 0 1 0 0
0 0 0 0 0 0 1
0 0 0 1 0 0 0];
Is it possible to do this without for loop? Thanks

Answers (3)

Azzi Abdelmalek
Azzi Abdelmalek on 15 Oct 2013
Edited: Azzi Abdelmalek on 15 Oct 2013
A=[1;5;7;4];
B=zeros(numel(A),max(A))
B(sub2ind(size(B),(1:numel(A))',A))=1

Vivek Selvam
Vivek Selvam on 15 Oct 2013
Edited: Vivek Selvam on 21 Oct 2013
Hi Theodor,
You can try a look-up table like this:
lut = logical(diag(ones(1,7)));
A = [1 5 7 4]';
S = lut(A(:),:);

hayim
hayim on 13 Jan 2014
Late to the party, but how about this?
A = [1 5 7 4]';
S = bsxfun(@eq,A,1:7)
ans =
1 0 0 0 0 0 0
0 0 0 0 1 0 0
0 0 0 0 0 0 1
0 0 0 1 0 0 0
bsxfun is your friend!

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