what does jj = (1:12) mean in matlab

In MATLAB, jj = (1:12) creates an array jj containing the numbers 1 through 12. This is equivalent to manually typing jj = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]. The : operator is used to create a range of numbers, in this case from 1 to 12.