Conditionally replacing values in a matrix

Question

Say I have two matrices A = [ 1 0 0 1 ] and B = [ 9 9 7 6 ] .

If A(i) != 0 I want to replace B(i) with A(i) . Is there a built in function in Matlab that can do this? I don't want to use loops.

Answer 1

It is as simple as that:

B(A ~= 0) = A(A ~= 0) 

In Matlab not equal has the operator ~= as you could have found out in the documentation . And you should learn some basics about matrix indexing , in this case especially logical indexing .