python之permutations和combinations的区别

转载至http://blog.youkuaiyun.com/cain/article/details/6585513

import itertools

list(itertools.combinations('abc', 2))
#[('a', 'b'), ('a', 'c'), ('b', 'c')]
list(itertools.permutations('abc',2))
#[('a', 'b'), ('a', 'c'), ('b', 'a'), ('b', 'c'), ('c', 'a')('c', 'b')]