多态

1. 多态的一种方式

## 多态：同一种事务的多种状态
## 多态性指的是可以在不考虑对象具体类型的情况下而直接使用对象

class Animal:
	def say(self):
		print('动物基本的发声')

class Person(Animal):
	def say(self):
		super().say()
		print('啊啊啊啊啊啊啊啊')

class Dog(Animal):
	def say(self):
		super().say()
		print('汪汪汪')

class Pig(Animal):
	def say(self):
		super().say()
		print('哼哼哼')

person = Person()
dog = Dog()
pig = Pig()

## 定义统一的接口，实现多态
def animal_say(animal):
	animal.say()

animal_say(person)
animal_say(dog)
animal_say(pig)

## 多态的例子
def my_len(val):
    return val.__len__()

my_len('aini')
my_len([1,12,3,4,5,'hhh'])
my_len({'name':'yanchen','age':18})

2. Python推崇的多态

## 鸭子类型，不用继承

class Cpu:
	def read(self):
		print('cpu read')
		
	def write(self):
		print('cpu write')
		
class Meu:
	def read(self):
		print('meu read')

	def write(self):
		print('meu write') 
		
class Txt:
	def read(self):
		print('txt read')

	def write(self):
		print('txt write') 


cpu = Cpu()
meu = Meu()
txt = Txt()