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我试图找到一个集合的所有子集并将它们打印到一个列表中。但是，我目前遇到了这个错误。

错误：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "subset_of_set.py", line 15, in <module>
    print subsets(a)
  File "subset_of_set.py", line 9, in subsets
    return subsets(setys, count + 1, main_list.append(sublist))
  File "subset_of_set.py", line 9, in subsets
    return subsets(setys, count + 1, main_list.append(sublist))
AttributeError: 'NoneType' object has no attribute 'append'

但是当我.append在解释器上测试时，它似乎很好。

>>> f = []
>>> f.append(3)
>>> f
[3]

可能有一些我想念或不知道的东西。有人可以解释一下吗？谢谢你！

我的代码：

def subsets(setys, count = 1,main_list = []):
    set_to_list = list(setys)
    length_of_set = len(setys)
    sublist = []
    if count == length_of_set:
        return set(main_list)
    for n in set_to_list[:count]:
        sublist.append(n)
    return subsets(setys, count + 1, main_list.append(sublist))


a = [3,5,3,2,5,7,34,2,54,6,7,1,1,1,0,None,3,99,9]
a = set(a)

print subsets(a)
4

2 回答 2

2

return subsets(setys, count + 1, main_list.append(sublist))确实是您的错误所在。考虑将其更改为类似

main_list.append(sublist)
return subsets(setys, count + 1, main_list)
于 2013-10-14T06:19:39.627 回答
2

这里有两件事是错误的：

第一的

return set(main_list)

使用：return main_list 代替。

因为，Set 需要一个可散列类型，而 list 不是，因为 list 是可变的。你也可以在这里使用一个元组，它是不可变的。

其他

您不能同时将 main_list 的引用附加并传递给递归。所以像：

main_list.append(sublist)
    return subsets(setys, count + 1, main_list)

会为你工作。

输出：

[]
[[0]]
[[0], [0, 1], [0, 1]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99]]
[[0], [0, 1], [0, 1], [0, 1, 34], [0, 1, 34], [0, 1, 34], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99], [0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99]]

编辑

将此添加到您的退货声明中：

final_set = set()
        for item in tuple(main_list):
            final_set.add(tuple(item))
        return list(final_set)

最终输出：

[(0, 1), (0,), (0, 1, 34, 3, 5, 6, 7, 9, 2, None, 99), (0, 1, 34), (0, 1, 34, 3, 5, 6, 7, 9, 2), (0, 1, 34, 3, 5), (0, 1, 34, 3, 5, 6, 7), (0, 1, 34, 3, 5, 6, 7, 9), (0, 1, 34, 3, 5, 6), (0, 1, 34, 3, 5, 6, 7, 9, 2, None), (0, 1, 34, 3)]
于 2013-10-14T06:26:35.683 回答