python 组合_几个有用的python函数 (笛卡尔积, 排列, 组合) - kitt blog (欢迎留言，最近刷的题目放到github上了) - github我的刷题 https://git...

product 笛卡尔积

permutations 排列

combinations 组合,没有重复

combinations_with_replacement 组合,有重复

>>> import itertools

>>> for i in itertools.product('ABCD', repeat = 2):

... print i,

...

('A', 'A') ('A', 'B') ('A', 'C') ('A', 'D') ('B', 'A') ('B', 'B') ('B', 'C') ('B', 'D') ('C', 'A') ('C', 'B') ('C', 'C') ('C', 'D') ('D', 'A') ('D', 'B') ('D', 'C') ('D', 'D')

>>> for i in itertools.permutations('ABCD', 2):

... print i,

...

('A', 'B') ('A', 'C') ('A', 'D') ('B', 'A') ('B', 'C') ('B', 'D') ('C', 'A') ('C', 'B') ('C', 'D') ('D', 'A') ('D', 'B') ('D', 'C')

>>> for i in itertools.combinations('ABCD', 2):

... print i,

...

('A', 'B') ('A', 'C') ('A', 'D') ('B', 'C') ('B', 'D') ('C', 'D')

>>> for i in itertools.combinations_with_replacement('ABCD', 2):

... print i,

...

('A', 'A') ('A', 'B') ('A', 'C') ('A', 'D') ('B', 'B') ('B', 'C') ('B', 'D') ('C', 'C') ('C', 'D') ('D', 'D')