MATLAB: Finding nonzero elements in matrix

Question

Hello,

I have a matrix with the values of either zero or one; I want to find non zero elements in every coloumn and locate the indices of each non zero element in every coloumn of a new matrix. For example, let's say my original matrix looks like this:

a =

0 1 1

0 0 1

1 1 1

I want the indices of non zero element in a new matrix look like this:

b =

0 1 1

0 0 2

3 3 3

How can I do it? I tried with the find function but without any success.

Thanks in advance,

Tilek

Answer 1

iwant = zeros(size(A)) ; 
for i = 1:size(A,1)
  if any(A(i,:))
    iwant(i,A(i,:)~=0) = i ;
  end  
end