MATLAB: What is the shortest way to make matrix from a vector using the 1-of-K coding scheme

binaryclassificationmatrixvector

How to make matrix from a vector using the 1-of-K coding scheme but without a for cycle? (1,1,2,3,1,3,2) to (1,0,0; 1,0,0; 0,1,0; 0,0,1; 1,0,0; 0,0,1; 0,1,0)

Best Answer

This is easy using sub2ind:
>> C = [1,1,2,3,1,3,2];
>> R = 1:numel(C);
>> A = zeros(numel(C),max(C));
>> A(sub2ind(size(A),R,C)) = 1
A =
     1     0     0
     1     0     0
     0     1     0
     0     0     1
     1     0     0
     0     0     1
     0     1     0
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