python - Itertools 排列

Question

我有一个列表 x=[1,2,3,4,5] 并且想查看这个列表的不同排列，一次取两个数字。

x=[1,2,3,4,5] 
from itertools import permutations
y=list(i for i in permutations(x,2) if i[0]<i[1])
print(y)

输出:[(1, 2), (1, 3), (1, 4), (1, 5), (2, 3), (2, 4), (2, 5) , (3, 4), (3, 5), (4, 5)]

但我还想在输出中使用 [(1,1),(2,2),(3,3),(4,4),(5,5)]。如何纠正这个？

Answer 1

你想要combinations_with_replacement()相反:

>>> from itertools import combinations_with_replacement
>>> list(combinations_with_replacement(x, 2))
[(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (2, 2), (2, 3), (2, 4), (2, 5), (3, 3), (3, 4), (3, 5), (4, 4), (4, 5), (5, 5)]