How do I concatenate matrices in GAUSS?

Numerical data

For matrices and vectors use the tilde ~ operator for horizontal concatenation and the pipe | operator for vertical concatenation.

For example if you have two 3x1 vectors A and B, you can concatenate them into a 3x2 matrix like this:

A = { 1,
      2,
      3 };

B = { 4,
      5,
      6 };
new_mat = A ~ B;

will assign new_mat to be the following matrix:

1 4
2 5
3 6

You could vertically concatenate them into a 6x1 vector like this:

A = { 1,
      2,
      3 };

B = { 4,
      5,
      6 };
new_mat = A | B;

will assign new_mat to be the following vector:

1
2
3
4
5
6

String Arrays

String arrays use the tilde ~ and pipe | operators, but they are prepended with the dollar sign $. For example:

string sa_A = { "alpha",
                "beta" };
string sa_B = { "gamma",
                "delta" };

// Horizontal string concatenation
sa_C = sa_A $~ sa_B;

// Vertical string concatenation
sa_D = sa_A $| sa_B;

after the code above:

sa_C = "alpha" "gamma"
       "beta"  "delta"

sa_D = "alpha"
       "beta"
       "gamma"
       "delta"