列出字符串/整数的所有排列

def get_permutations(arr):
    if len(arr) == 0:
        return []
    if len(arr) == 1:
        return [arr]
    permutations = []
    for i in range(len(arr)):
        rest = arr[:i] + arr[i+1:]
        for p in get_permutations(rest):
            permutations.append([arr[i]] + p)
    return permutations

arr = [1, 2, 3]
permutations = get_permutations(arr)
print(permutations)

[[1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 1, 2], [3, 2, 1]]

arr = "abc"
permutations = get_permutations(list(arr))
for p in permutations:
    print("".join(p))

abc
acb
bac
bca
cab
cba