在Python中迭代给定类的对象实例

import gc

class MyClass:
    pass

instance1 = MyClass()
instance2 = MyClass()

for obj in gc.get_objects():
    if isinstance(obj, MyClass):
        print(obj)

import weakref

class MyClass:
    instances = set()

    def __init__(self):
        self.__class__.instances.add(weakref.ref(self))

    @classmethod
    def get_instances(cls):
        dead_refs = set()
        for ref in cls.instances:
            obj = ref()
            if obj is not None:
                yield obj
            else:
                dead_refs.add(ref)
        cls.instances -= dead_refs

instance1 = MyClass()
instance2 = MyClass()

for instance in MyClass.get_instances():
    print(instance)