将值插入列表中所有可能的位置 [英] Inserting a value into all possible locations in a list

问题描述

我正在尝试打印给定列表的所有可能结果，并且我想知道如何将值放入列表中的各个位置.例如，如果我的列表是[A, B]，我想将X插入到列表的所有可能的索引中，这样它将返回此[X, A, B]，[A, X, B]，[A, B, X].

I am trying to do print all the possible outcomes of a given list and I was wondering how to put a value into various locations in the list. For example, if my list was [A, B], I want to insert X into all possible index of the list such that it would return this [X, A, B], [A, X, B], [A, B, X].

我正在考虑使用range(len())和for循环，但不确定如何启动.

I was thinking about using range(len()) and a for loop but not sure how to start.

推荐答案

您可以通过以下列表理解来做到这一点:

You could do this with the following list comprehension:

[mylist[i:] + [newelement] + mylist[:i] for i in xrange(len(mylist),-1,-1)]

以您的示例为例:

>>> mylist=['A','B']
>>> newelement='X'
>>> [mylist[i:] + [newelement] + mylist[:i] for i in xrange(len(mylist),-1,-1)]
[['X', 'A', 'B'], ['B', 'X', 'A'], ['A', 'B', 'X']]

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