在Python中，如何创建可变长度的组合或排列? [英] In Python how do I create variable length combinations or permutations?

问题描述

假设我有一个名为arr = [1,2,3,4]的数组

Lets say I have an array called arr = [1,2,3,4]

如何生成带有至少2个参数的所有可能组合，最终看起来像这样

How can I generate all the possible combinations with minimum 2 arguments that end up looking like

[1,2]
[1,3]
[1,4]
[1,2,3]
[1,2,4]
[1,2,3, 4]
[2,3]
[2,4]

等等，依此类推?我没有尝试的方法.我似乎无法使用itertools.combinations或置换，因为我需要知道参数的大小，而我似乎无法使用itertools.products，因为它将从看起来像 [[1]，[2]，[3]，[4]，[5]] .特别感谢您的班轮和理解.

and so on and so forth? Nothing Im trying works. I cant seem to use itertools.combinations or permutations because I need to know the argument size and I cant seem to use itertools.products because that will take minimum one argument from each of a list of lists that looks like this [[1],[2],[3],[4],[5]]. Extra thanks for one liners and comprehensions.

如果我想将它们全部加在一起，那么就需要太多帮助了吗?;-)

If I wanted to add them all together would that be too much to ask in terms of help? ;-)

推荐答案

怎么样:

(x for l in range(2, len(arr)) for x in itertools.combinations(arr, l))

或

[x for l in range(2, len(arr)) for x in itertools.combinations(arr, l)]

如果您需要列表.

这等效于以下嵌套循环

res = []
for l in range(2, len(arr)):
    for x in itertools.combinations(arr, l):
        res.append(x)
return res

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