How can I make this matrix function?

Let's say I have a matrix A[x,y,z]

If A[i,j,k]<N, (i<=x, j<=y, k<=z, N : certain value.)

then A[i,j,k]=0

else nothing happens.

I can make this function if I use "for" statement, but using "for" statement in matlab consumes a lot of time.

I'm sure there is a function that best fits what I want to do.

So, How can I make this function without using "for" statement?

Answer 1

[Harish Ramachandran]

This is an example of your use case on a 2-D matrix. The same is scalable for a 3-D matrix.

      X = rand(5)

      X =

          0.7577    0.7060    0.8235    0.4387    0.4898
          0.7431    0.0318    0.6948    0.3816    0.4456
          0.3922    0.2769    0.3171    0.7655    0.6463
          0.6555    0.0462    0.9502    0.7952    0.7094
          0.1712    0.0971    0.0344    0.1869    0.7547

    X(X<0.5) = 0;

    X =

        0.7577    0.7060    0.8235         0         0
        0.7431         0    0.6948         0         0
             0         0         0    0.7655    0.6463
        0.6555         0    0.9502    0.7952    0.7094
             0         0         0         0    0.7547