multi_list = [[0 for col in range(col_num)] for row in range(row_num)]

Question

Y we using 0 before the for loop ?

Answer 1

It will fill the multidimensional list with 0's. Run the code and print the list to see.

Answer 2

BTW your code was incomplete. It was missing definition for <row_num> and <col_num>. Once you complete it though, it's fine.