Python:计算列表的笛卡尔功效的最短方法 [英] Python: shortest way to compute cartesian power of list

问题描述

假设我们有一个列表L.笛卡尔积L x L可以这样计算:

Suppose we have a list L. The cartesian product L x L could be computed like this:

product = [(a,b) for a in L for b in L]

如何以短而有效的方式计算笛卡尔乘方L x L x L x ... x L(对于给定的n，n次)?

How can the cartesian power L x L x L x ... x L (n times, for a given n) be computed, in a short and efficient way?

推荐答案

使用 itertools.product() :

product = itertools.product(L, repeat=n)

其中product现在是可迭代的；如果您想将其具体化为完整列表，请致电list(product):

where product is now a iterable; call list(product) if you want to materialize that to a full list:

>>> from itertools import product
>>> list(product(range(3), repeat=2))
[(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2), (2, 0), (2, 1), (2, 2)]

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