Extracting multiple matrix from a single matrix

I have a matrix(type double) similar to the following example:

    X = [ 23 3 5 1; 
          21 45 8 1; 
          65 56 7 1; 
          71 42 4 2; 
          45 91 5 2; 
          34  6 1 3; 
          87 37 8 3;  
          23 3 5  3]

Based on the element of the fourth column I want to get 3 matrix from the above matrix like the following example;

        A=[ 23 3 5 1;         
            21 45 8 1; 
            65 56 7 1; ]

        B =[ 71 42 4 2; 
             45 91 5 2; ]

      C =[ 34  6 1 3; 
           87 37 8 3;  
           23 3 5  3;]

Basically I want to seprate all the 1s,2s and 3s of the fourth column into another matrix. How can I do it in the Matlab!

Answer 1

[Walter Roberson]

A = X( X(:,4) == 1, :);
B = X( X(:,4) == 2, :);
C = X( X(:,4) == 3, :);