rotate_square_matrix_90_deg_right.py

#!/usr/bin/env python3
"""
see also:
https://gist.github.com/danquixote/64d12eebef39c50f4adf2204d6dbf2ef
"""

MATRIX = [
    [1,2,3],
    [4,5,6],
    [7,8,9],
]

"""matrix out:
    7,4,1
    8,5,2
    9,6,3
"""

def rotate_square_matrix_90_deg_right(matrix):
    outer_list = []
    matrix = list(reversed(matrix))
    for ii in range(0, len(matrix)):
        lst = []
        for row in matrix:
            lst.append(row[ii])
            if len(lst) == len(row):
                outer_list.append(lst)
    return outer_list


if __name__ == '__main__':
    print(rotate_square_matrix_90_deg_right(MATRIX))

Please see the more extensible version at:
https://gist.github.com/danquixote/64d12eebef39c50f4adf2204d6dbf2ef