MATLAB: Isn’t this threshold loop working

Question

I've created a simple loop to go through a 1024×240 array to set all values below the threshold of 0.04 to NaN.

 for freqs = 1:F
    for times = 1:T
        if P(times,freqs) < 0.04
            P(times,freqs) = NaN
        end
    end
end

I tested the same style of loop for a much smaller magic(x) array and got the exact results expected. The "P" array has plenty of 0's in it as well as (n)e-3, so seeing that nothing was happening was quite easy. Is there a simpler solution at that I'm unaware of or is there just something I'm oblivious to?

Answer 1

Try

nanMask = P < 0.04;
P(nanMask) = NaN;