Python子类判断issubclass和实例判断isinstance

# -*- coding: utf-8 -*-


class Animal(object):
    pass


class Cat(Animal):
    pass


class Dog(Animal):
    pass


cat = Cat()

print(issubclass(Cat, Animal))  # True

print(isinstance(cat, Animal))  # True
print(isinstance(cat, Cat))  # True
print(isinstance(cat, Dog))  # False

# 两种方式等价
print(isinstance(cat, (Cat, Dog)))  # True
print(isinstance(cat, Cat) or isinstance(cat, Dog))  # True

# -- coding: utf-8 --


class A(object):
    pass


class B(A):
    pass


class C(A):
    pass


for clazz in A.__subclasses__():
    print(clazz.__name__)
# B C