Python 3中的嵌套列表的对角线

Question

I have a several lists within a list which forms a game of noughts and crosses:

list = [
        ['X', 'O', 'O'], 
        ['O', 'X', 'O'], 
        [' ', 'X', ' ']
       ]

I need to write a function that returns the diagonals of the game from top left to bottom right and then top right to bottom left so the output would be:

diags = (['X', 'X', ' '],['O', 'X', ' '])

I have tried various combinations of nested for loops, can't seem to get my head around it though.

Answer 1

nw_to_se = [your_list[i][i] for i in range(3)]
ne_to_sw = [your_list[i][2-i] for i in range(3)]
diags = (nw_to_se, ne_to_sw)

Instead of [2-i] you could also use [-i-1] , which scales to any size square.