map a matrix with another matrix

Question

I have a question to the mapping of a matrix with another matrix which contains only 1 and 0. Here an example of my problem: A is the matrix with doubles

Answer 1

Just multiply A and B element-wise:

C = A.*B

Answer 2

I like Dan's solution, but this would be another way:

C = zeros(size(A));
C(B==1) = A(B==1);