多态与多态性

instantiate abstract class Animal with abstract methods eat, speak：用抽象方法实例化抽象类动物吃，说

'''
1 什么是多态
    多态指的是同一种事物的多种形态
        水-》冰、水蒸气、液态水
        动物-》人、狗、猪

2 为和要用多态
    多态性：
    继承同一个类的多个子类中有相同的方法名
    那么子类产生的对象就可以不用考虑具体的类型而直接调用功能

3 如何用
'''
import abc


class Animal(metaclass=abc.ABCMeta):
    @abc.abstractmethod  # 强制子类用父类制定的标准
    def speak(self):
        pass

    @abc.abstractmethod
    def eat(self):
        pass


# Animal() #强调：用了装饰器后,父类是用来指定标准的，不能被实例化,会报错

class People(Animal):
    def speak(self):
        print('say hello')

    def eat(self):
        pass


class Dog(Animal):
    def speak(self):
        print('汪汪汪')

    def eat(self):
        pass


class Pig(Animal):
    def speak(self):
        print('哼哼哼')

    def eat(self):
        pass


peo1 = People()
dog1 = Dog()
pig1 = Pig()


#
#
# peo1.speak()
# dog1.speak()
# pig1.speak()

# def my_speak(animal):
#     animal.speak()
#
# my_speak(peo1)
# my_speak(dog1)
# my_speak(pig1)

#
# l=[1,2,3]
# s='helllo'
# t=(1,2,3)
#
# print(l.__len__())
# print(s.__len__())
# print(t.__len__())
#
# # def len(obj):
# #     return obj.__len__()
#
# print(len(l)) # l.__len__()
# print(len(s)) #s.__len__()
# print(len(t))


# python推崇的是鸭子类型，只要你叫的声音像鸭子，并且你走路的样子也像鸭子，那你就是鸭子

class Disk:
    def read(self):
        print('disk read')

    def write(self):
        print('disk wirte')


class Process:
    def read(self):
        print('process read')

    def write(self):
        print('process wirte')


class File:
    def read(self):
        print('file read')

    def write(self):
        print('file wirte')


obj1 = Disk()
obj2 = Process()
obj3 = File()

obj1.read()
obj1.write()

obj2.read()