index errors

[ThomasL]

What you want to do is called flattening

import random

m = [[[random.randint(0,4) for i in range(2)] for k in range(4)] for i in range(3)]
print(m)

def flatten(matrix):
    flat = []
    for dim1 in matrix:
        for dim2 in dim1:
            for element in dim2:
                flat.append(element)
    return flat

print(flatten(m))

and that flattening can be coded as one line

def flatten(matrix):
    return [element for dim1 in matrix for dim2 in dim1 for element in dim2]