How to convert integer vector with the 1-of-K coding sheme into a matrix?

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I have Y = [2 2 1 3 2 4 1 4 4 3]; And I need 4 x 10 matrix in which all values are zeros, except 2nd element in the 1st column, 2nd element in the 2nd column, 1st element in the 3rd column etc. they are all ones.

Answers (2)

Jos (10584)
Jos (10584) on 30 Jan 2018
Here are two easy one-liners:
Y = [2 2 1 3 2 4 1 4 4 3];
M1 = full(sparse(Y,1:10,1))
M2 = accumarray([Y(:) (1:10).'], 1)

Andrei Bobrov
Andrei Bobrov on 30 Jan 2018
Y = [2 2 1 3 2 4 1 4 4 3];
m = max(Y);
n = numel(Y);
out = zeros(m,n);
out( sub2ind([m,n],Y,1:n )) = 1

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