How to split sub-lists into sub-lists k times? (Python)

Question

I know that I can split a list into sub-lists of equal size using:

segment = len(list)//k
sub_lists = [list[i:i+segment] for i in range(0, len(list), segment)]

However I'm not sure how to split a list of length k^m into sub-lists, then further sub-lists until each sub-list has length of 1.

For example:

k = 2
list = [1, 2, 3, 4, 5, 6, 7, 8]
list = [[1, 2, 3, 4], [5, 6, 7, 8]]
list = [[[1, 2], [3, 4]], [[5, 6], [7, 8]]]
list = [[[[1], [2]], [[3], [4]]], [[[5], [6]], [[7], [8]]]]

Whenever I've tried to loop this I get tied in knots, is there a short-cut?

Answer 1

This is essentially your code:

def split_list(input_list, segments):
    if len(input_list) == 1:
        return input_list
    segment_length = len(input_list) // segments
    return [split_list(input_list[i:i+segment_length], segments) 
            for i in range(0, len(input_list), segment_length)]

>>> split_list([1, 2, 3, 4, 5, 6, 7, 8], 2)
[[[[1], [2]], [[3], [4]]], [[[5], [6]], [[7], [8]]]]

Answer 2

def sub_k_list(a, k):
    p = len(a) // k
    return a if not p else [sub_k_list(a[:p], k), sub_k_list(a[p:], k)]

k = 2
a = [1, 2, 3, 4, 5, 6, 7, 8]

print(sub_k_list(a, k))

Result:

[[[[1], [2]], [[3], [4]]], [[[5], [6]], [[7], [8]]]]

Edit: remove the if ...

def sub_k_list(a, k):
    p = len(a) // k
    return a * (not p) or [sub_k_list(a[:p], k), sub_k_list(a[p:], k)]