MATLAB: Substituting value in matrix does not work for some reason

Question

A = [6 9 NaN NaN 8 NaN]; B = [2 5 342 232 1 116];

sizeA = size(A);

for m = [1:1:size(2)];

    if A(1,m) == NaN;
       B(1,m) = NaN;
    end;
end;

I was hoping B would become [2 5 NaN NaN 8 NaN], but it did not change. I would appreciate any help

Answer 1

You can't use == with NaNs:

>> NaN == NaN
ans =
       0

Use isnan instead:

B(isnan(A)) = NaN;