第一种方法：递归

复制代码 代码如下:

def perms(elements):

if len(elements) <=1:

yield elements

else:

for perm in perms(elements[1:]):

for i in range(len(elements)):

yield perm[:i] + elements[0:1] + perm[i:]

for item in list(perms([1, 2, 3,4])):

print item

结果

复制代码 代码如下:

[1, 2, 3, 4]

[2, 1, 3, 4]

[2, 3, 1, 4]

[2, 3, 4, 1]

[1, 3, 2, 4]

[3, 1, 2, 4]

[3, 2, 1, 4]

[3, 2, 4, 1]

[1, 3, 4, 2]

[3, 1, 4, 2]

[3, 4, 1, 2]

[3, 4, 2, 1]

[1, 2, 4, 3]

[2, 1, 4, 3]

[2, 4, 1, 3]

[2, 4, 3, 1]

[1, 4, 2, 3]

[4, 1, 2, 3]

[4, 2, 1, 3]

[4, 2, 3, 1]

[1, 4, 3, 2]

[4, 1, 3, 2]

[4, 3, 1, 2]

[4, 3, 2, 1]

第二种方法：python标准库

复制代码 代码如下:

import itertools

print list(itertools.permutations([1, 2, 3,4],3))

源代码如下：

复制代码 代码如下:

#coding:utf-8

import itertools

print list(itertools.permutations([1, 2, 3,4],3))

def perms(elements):

if len(elements) <=1:

yield elements

else:

for perm in perms(elements[1:]):

for i in range(len(elements)):

yield perm[:i] + elements[0:1] + perm[i:]

for item in list(perms([1, 2, 3,4])):

print item