matrix arrangement problem for loop

hey guide i want arrangement the matrix like: a = [1 2 3 4 5 6 7 8.........unknown number] but matrix is A multiple of four

how to use for loop to become

a = [1 2 3 4; 5 6 7 8; 9 ....; .....unknown number];

Answer 1

[Roger Stafford]

a = reshape(a,4,[]).';

[tsai kai shung]

thank you