Simple Matrix Reduction Question. Ones and Zeros.

I have a NxM matrix full of ones and zeros. Each row (1:N) has exactly one, one, somewhere along of the columns. I want to make a matrix Nx1 which shows which columns the ones appeared in. Example:

A = [ 0 0 0 1; 1 0 0 0; 0 1 0 0; 0 0 1 0]

B = [ 4 ; 1 ; 2 ; 3 ]

Should be very simple?

Answer 1

[Birdman]

[rows,cols]=find(A==1);
[C,I]=sort(rows);
B=cols(I)

Answer 2

[Stephen23]

Simpler:

>> [B,~] = find(A.')
B =
   4
   1
   2
   3