Simple question about vector remainders

So I have one vector x = [19 21 25 24 18 20]

I need to use this vector to find another vector that contains only the amounts over 20. So it should look something like x = [0 1 5 4 0 0].

This seems like it should be incredibly simple but it is giving me grief. The only thing I have tried that has come relatively close is something like b = (x-20)>0 which simply returns that certain values are true to be over 20(i.e. b = 0 1 1 1 0 0.)

I've also tried declaring another vector w = [20 20 20 20 20 20] and then doing z = w - x but that returns some negative results in the vector.

Any help is greatly appreciated.

Answer 1

[Matt Fig]

y = mod(x,20).*(x>20) % if no x>40

Or if some value may be greater than 40,

y = max(x-20,0)

Answer 2

[Azzi Abdelmalek]

 y=(x-20).*(x>20)