Python：找到从这个继承的所有类？ [重复]

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How to find all the subclasses of a class given its name? 10 answers

如何根据名称查找类的所有子类? 10个答案

Is there any way in python to query a namespace for classes which inherit from a particular class? Given a class widget I'd like to be able to call something like inheritors(widget) to get a list of all my different kinds of widget.

在python中是否有任何方法可以查询从特定类继承的类的命名空间?给定一个类小部件,我希望能够调用类似继承者(小部件)的东西来获取我所有不同类型小部件的列表。

4 个解决方案

#1

You want to use Widget.__subclasses__() to get a list of all the subclasses. It only looks for direct subclasses though so if you want all of them you'll have to do a bit more work:

您想使用Widget .__ subclasses __()来获取所有子类的列表。它只查找直接子类,但如果你想要所有这些,你将不得不做更多的工作:

def inheritors(klass):
    subclasses = set()
    work = [klass]
    while work:
        parent = work.pop()
        for child in parent.__subclasses__():
            if child not in subclasses:
                subclasses.add(child)
                work.append(child)
    return subclasses

N.B. If you are using Python 2.x this only works for new-style classes.

注:如果您使用的是Python 2.x,则仅适用于新式类。

#2

You can track inheritance with your own metaclass

您可以使用自己的元类跟踪继承

import collections

class A(object):
    class __metaclass__(type):
        __inheritors__ = defaultdict(list)

        def __new__(meta, name, bases, dct):
            klass = type.__new__(meta, name, bases, dct)
            for base in klass.mro()[1:-1]:
                meta.__inheritors__[base].append(klass)
            return klass

class B(A):
    pass

class C(B):
    pass

>>> A.__inheritors__
defaultdict(<type 'list'>, {<class '__main__.A'>: [<class '__main__.B'>, <class '__main__.C'>], <class '__main__.B'>: [<class '__main__.C'>]})

Anything that is inherited from A or it's derived classes will be tracked. You will get full inheritance map when all the modules in your application are loaded.

将跟踪从A或其派生类继承的任何内容。加载应用程序中的所有模块后,您将获得完整的继承映射。

#3

# return list of tuples (objclass, name) containing all subclasses in callers' module
def FindAllSubclasses(classType):
    import sys, inspect
    subclasses = []
    callers_module = sys._getframe(1).f_globals['__name__']
    classes = inspect.getmembers(sys.modules[callers_module], inspect.isclass)
    for name, obj in classes:
        if (obj is not classType) and (classType in inspect.getmro(obj)):
            subclasses.append((obj, name))
    return subclasses

#4

You have to walk through all objects in the global namespace (globals()) and check if the related object/class is a subclass of the some other class (check the Python docs for issubclass()).

您必须遍历全局命名空间中的所有对象(globals())并检查相关对象/类是否是其他类的子类(请查看issubclass()的Python文档)。

#1