n项的组合数

orl*_*rlp 5

您所描述的是n 个对象的排列数。有n个！= 1 × 2 × ... × n（也称为n factorial）这样的排列。

Ism*_*ana 5

您需要置换的n条件，itertools有排列方法。您可以按如下方式使用它：

import itertools

lst = ['A', 'B', 'C', 'D']
z = itertools.permutations(lst, len(lst))

print(list(z))

如果你想了解更多：https : //docs.python./3/library/itertools.html#itertools.permutations

import itertools

def permutations(iterable, r=None):
    pool = tuple(iterable)
    n = len(pool)
    r = n if r is None else r
    for indices in itertools.product(range(n), repeat=r):
        if len(set(indices)) == r:
            yield tuple(pool[i] for i in indices)

lst = ['A', 'B', 'C', 'D']
z = permutations(lst, len(last))

print(list(z))