如何实现枚举嵌套类的函数？

class A(object):
    class B(object):
        pass

    class C(object):
        pass


def enumerate_nested_classes(_class):
    return ()  # need proper implementation instead


assert set(enumerate_nested_classes(A)) == {A.B, A.C}

解决方法:

您可以使用下一个代码：

import types


class A(object):
    class B(object):
        pass

    class C(object):
        pass

def enumerate_nested_classes(_class):
    return [getattr(_class, n) for n in dir(_class) if not n.startswith('__')
            and isinstance(getattr(_class, n), (type, types.ClassType))] 

assert enumerate_nested_classes(A) == [A.B, A.C]

并打印enumerate_nested_classes(A)打印[< class'__main __.B'>,< class'__main __.C'>]

NB. dir(_class)结果列表按字母顺序排序,因此当使用assert enumerate_nested_classes(A)== [A.B,A.C]时,最好使用：assert sorted(enumerate_nested_classes(A))== sorted([A.B,A.C]).