CODEWITHSUNDEEP
pythonlist
JDraper
JDraper

Reputation: 359

Possible combinations of multiple lists

I have a set of variables in a list

list = [ 'A', 'B', 'C']

I iteratively remove one variable from the list and append this to the original list in a list of lists, stopping when the list only has one item. For example, the output using the list above would be:

list_of_var_lists = [
[['A', 'B', 'C'], ['A', 'B'], ['A']],
[['A', 'B', 'C'], ['A', 'B'], ['B']],
[['A', 'B', 'C'], ['A', 'C'], ['A']],
[['A', 'B', 'C'], ['A', 'C'], ['C']],
[['A', 'B', 'C'], ['B', 'C'], ['B']],
[['A', 'B', 'C'], ['B', 'C'], ['C']]
]

How would i do for a list of any size?

Many thanks, J

Upvotes: 2

Views: 71

Answers (1)

John Coleman
John Coleman

Reputation: 52008

Here is a solution using itertools.permutations. It is a generator rather than a massive lists of lists of lists, since the number of such sublists grows hyper-exponentially:

import itertools

def list_unpacker(ls):
    for p in itertools.permutations(ls):
        sublists = []
        current_list = ls[:]
        sublists.append(current_list)
        for x in p[:-1]:
            current_list = [y for y in current_list if y != x]
            sublists.append(current_list)
        yield sublists

for lists in list_unpacker(['a','b','c']):
    print(lists)

Output:

[['a', 'b', 'c'], ['b', 'c'], ['c']]
[['a', 'b', 'c'], ['b', 'c'], ['b']]
[['a', 'b', 'c'], ['a', 'c'], ['c']]
[['a', 'b', 'c'], ['a', 'c'], ['a']]
[['a', 'b', 'c'], ['a', 'b'], ['b']]
[['a', 'b', 'c'], ['a', 'b'], ['a']]

Upvotes: 4

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