如何获得列表的所有组合？

Question

我正在尝试获取列表的所有组合。 这是一个例子：

>>> l = [1, 2, 3]
>>> combo = something
>>> print(combo)
[1, 2, 3, 12, 13, 21, 23, 31, 32, 123, 132, 213, 231, 312, 321]

这是我到目前为止所尝试的：

>>> import itertools
>>> numbers = [1, 2, 3]
>>> l = list(itertools.permutations(numbers))
>>> print(l)
[(1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1)]

如何获得 output [1, 2, 3, 12, 13, 21, 23, 31, 32, 123, 132, 213, 231, 312, 321] ？

Answer 1

工作代码：

import itertools

numbers = [1, 2, 3]
result = []
for n in range(1, len(numbers) + 1):
    for x in itertools.permutations(numbers, n):  # n - length of each permutation
        result.append(int(''.join(map(str, x))))
print(result)

Output：

[1, 2, 3, 12, 13, 21, 23, 31, 32, 123, 132, 213, 231, 312, 321]

Answer 2

我相信您正在查看的 function 是：

 itertools.combinations(iterable, r)

它在r元素中组合了可迭代的数组。

所以：

>>> import itertools
>>> numbers = [1,2,3]
>>> l = list(itertools.combinations(numbers,2)) # combinations of two
>>> print(l)
[(1, 2), (1, 3), (2, 3)]

您可以在文档中获得更多详细信息。