python(7)–类的多态实现

class Animal:
    def __init__(self, name):
        self.name = name
    
    #这个方法的意思是，如果继承该类，就得自己写talk方法，如果不写，就抛出异常
    def talk(self):
        raise NotImplementedError("subclass must implement abstract method")

class Cat(Animal):
    def talk(self):
        return "Meow!"

class Dog(Animal):
    def talk(self):
        return "woof! woof!"

def animal_talk(obj):
    print(obj.talk())

cat = Cat("Missy")
dog = Dog("lassie")

animal_talk(cat)
animal_talk(dog)

animals = [Cat("Missy"), Dog("lassie")]

for i in animals:
    print("%s:%s" % (i.name, i.talk()))