所有对对python

Question

给定一个列表l=range(n)，如何迭代该列表中所有不同对的不同对。

例如，如果l = [0,1,2,3]我希望[((0,1), (0,2)),((0,1),(0,3)), ((0,1),(1,2)), ((0,1), (1,3)),((0,1), (2,3)), ((0,2), (0,3)), ((0,2),(1,2)),((0,2),(1,3)),((0,2),(2,3))...

Answer 1

您可以使用itertools.combinations：

from itertools import combinations

for pair in combinations(combinations(l, 2), 2):
    # use pair

第一个调用会创建初始对：

>>> l = [0,1,2,3]
>>> list(combinations(l, 2))
[(0, 1), (0, 2), (0, 3), (1, 2), (1, 3), (2, 3)]

第二次将它们配对：

>>> list(combinations(combinations(l, 2), 2))
[((0, 1), (0, 2)), ((0, 1), (0, 3)), ((0, 1), (1, 2)), ((0, 1), (1, 3)), 
 ((0, 1), (2, 3)), ((0, 2), (0, 3)), ((0, 2), (1, 2)), ((0, 2), (1, 3)), 
 ((0, 2), (2, 3)), ((0, 3), (1, 2)), ((0, 3), (1, 3)), ((0, 3), (2, 3)), 
 ((1, 2), (1, 3)), ((1, 2), (2, 3)), ((1, 3), (2, 3))]