MATLAB: Operations in a row only on certain elements

Question

Hi,

I have a row in a matrix, say A(1,:). I also have a vector b which its elemants are indices, I want to set to zero elements in A(1,:) where its index is NOT included in b. How can I do this?

Example:

A=[1 3 4; 5 6 2; 1 4 2]

b=[ 3 2]

So for the first row of A, I want to have A=[0 3 4; 5 6 2; 1 4 2]

the 2nd and 3rd index are not set to zero.

Thanks in advance.

Answer 1

See if this works:

idx(b) = true;
A(1,~idx) = 0;