copying values using if statements

I am trying to write an if statement for a give matrix.

I have a matrix that is 54,1, with given values.

What I want it to do is that if the value is greater that 0, to make it equal to that value in the given matrix, and if the value is less than 0, to make it equal to 0.

Answer 1

[Honglei Chen]

say x is your matrix

x = randn(54,1);
x(x<0)= 0