Python学习笔记（六）——类和对象

1.self的用法

全面理解self

2. 继承

子类继承父类，自动拥有父类的全部方法

>>> class Animal:

	def run(self):

		print('Animal is running !')

>>> class Dog(Animal):

	pass

>>> class Cat(Animal):

	pass

>>> dog = Dog()

>>> dog.run()

Animal is running !

>>> cat = Cat()

>>> cat.run()

Animal is running !

子类和父类拥有相同名称的函数，覆盖父类函数

>>> class Dog(Animal):

	def run(self):

		print('Dog is running')

>>> class Cat(Animal):

	def run(self):

		print('Cat is running')

>>> dog = Dog()

>>> dog.run()

Dog is running

>>> cat = Cat()

>>> cat.run()

Cat is running

3.组合

class Turtle:

    def __init__(self,x):

        self.num = x

class Fish:

    def __init__(self,x):

        self.num = x

class Pool:

    def __init__(self,x,y):

        self.turtle = Turtle(x)

        self.fish = Fish(y)

    def print_num(self):

        print("水池里总共有乌龟%d只，小鱼%d只" % (self.turtle.num,self.fish.num))

  >>> pool = Pool(15,20)

  >>> pool.print_num()

  水池里总共有乌龟15只，小鱼20只

4.相关的BIF

类和对象BIF大全

一个没有感情的笔记搬运工