如何以所有可能的方式将列表拆分成对 [英] How to split a list into pairs in all possible ways

问题描述

我有一个列表(为简单起见，说 6 个元素)

L = [0, 1, 2, 3, 4, 5]

并且我想以所有可能的方式将其分成两部分.我展示了一些配置:

[(0, 1), (2, 3), (4, 5)][(0, 1), (2, 4), (3, 5)][(0, 1), (2, 5), (3, 4)]

等等.这里 (a, b) = (b, a) 并且对的顺序并不重要，即

[(0, 1), (2, 3), (4, 5)] = [(0, 1), (4, 5), (2, 3)]

此类配置的总数为1*3*5*...*(N-1)，其中N 是我的列表长度.>

如何用 Python 编写一个生成器，为我提供任意 N 的所有可能配置?

解决方案

看看 itertools.combinations.

matt@stanley:~$ pythonPython 2.6.5(r265:79063，2010 年 4 月 16 日，13:57:41)[GCC 4.4.3] 在 linux2输入帮助"、版权"、信用"或许可"以获取更多信息.>>>导入迭代工具>>>列表(itertools.combinations(范围(6)，2))[(0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5), (3, 4), (3, 5), (4, 5)]

I have a list (say 6 elements for simplicity)

L = [0, 1, 2, 3, 4, 5]

and I want to chunk it into pairs in ALL possible ways. I show some configurations:

[(0, 1), (2, 3), (4, 5)]
[(0, 1), (2, 4), (3, 5)]
[(0, 1), (2, 5), (3, 4)]

and so on. Here (a, b) = (b, a) and the order of pairs is not important i.e.

[(0, 1), (2, 3), (4, 5)] = [(0, 1), (4, 5), (2, 3)]

The total number of such configurations is 1*3*5*...*(N-1) where N is the length of my list.

How can I write a generator in Python that gives me all possible configurations for an arbitrary N?

解决方案

Take a look at itertools.combinations.

matt@stanley:~$ python
Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41) 
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import itertools
>>> list(itertools.combinations(range(6), 2))
[(0, 1), (0, 2), (0, 3), (0, 4), (0, 5), (1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5), (3, 4), (3, 5), (4, 5)]

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