takespecific elements from matrix to build new one

hey everybody i have 40*10 matrix i want to build new one that contain the first 10 rows (1:10,:) and the third 10 rows (31:40,:) so the new matrix will contain 20*10 . thanks in advance.

Answer 1

[Chris C]

If your original matrix is called A, then

B = [A(1:10,:); A(31:end,:)];