ismember function can do the job. As it's stated in the doc page, "Lia = ismember(A,B) returns an array containing logical 1 (true) where the data in A is found in B."
Please try the following do see what it does.
b = magic(4)
a = [1,2,3,4];
I = ismember(b,a)
b(I) = 0
