用for循环将n个值的元组拆包?

问题描述

我正在做排列,我想以一种特定的方式打印结果。

我的代码

    from itertools import permutations as p

    n = 3      #This can be change

    permu_lst = [i for i in p(range(1,n+1)]

    for a,b,c in permu_lst:
       print(a,c)

    Output: 
    1 2 3
    1 3 2
    2 1 3
    2 3 1
    3 1 2
    3 2 1

所以我的问题是,n更改时,如何自动执行for循环以打印结果。

解决方法

您可以通过定义一个以n作为参数的函数来对此进行概括:

from itertools import permutations as p
def print_permutations(n):
    permu_lst = [i for i in p(range(1,n+1))]

    for per in permu_lst:
       print(*per)

per前的*将元组解包。

,

使用iterable unpacking operator(*)

from itertools import permutations as p

n = 4      #This can be change
permu_lst = [i for i in p(range(1,n+1))]

for tup in permu_lst:
    print(*tup)

输出:

1 2 3 4
1 2 4 3
1 3 2 4
1 3 4 2
1 4 2 3
1 4 3 2
2 1 3 4
2 1 4 3
2 3 1 4
2 3 4 1
2 4 1 3
2 4 3 1
3 1 2 4
3 1 4 2
3 2 1 4
3 2 4 1
3 4 1 2
3 4 2 1
4 1 2 3
4 1 3 2
4 2 1 3
4 2 3 1
4 3 1 2
4 3 2 1
​

参考:https://www.python.org/dev/peps/pep-0448/