Python 8 类和对象

类的基本定义

class 关键字 ：

        成员方法

注：关键字首字母要大写

实例化对象：

      class  Car():

               def glaring(self):

                      print("my name is Olive Queen")

      a=Car()

      a.glaring()

      my name is Olive Queen

公有和私有

________________________________________

>>> class Person:            

    name="666"

>>> a=Person()

>>> a.name                    #公有成员直接访问

'666'

________________________________________

>>> class Person:

    __name="666"

    def getname(self):

        return self.__name

>>> a=Person()

>>> a.getname()       #私有成员内部访问（内部函数）

'666'

________________________________________

>>> class Person:

    __name="666"

>>> a=Person

>>> a._Person__name       #私有成员通过“_类名__对象名”访问

'666'

继承

import random as r

class Fish:               #基类

    def __init__(self):

        self.x = r.randint(0,10)

        self.y = r.randint(0,10)

    def move(self):

        self.x =self.x -1

        print("我的位置是：",self.x,self.y)

class Goldfish(Fish):        #子类

    pass

class Carp(Fish):               #子类

    pass

class Salmon(Fish):             #子类

    pass

class Shark(Fish):               #子类

    def __init__(self):

        super().__init__()           #super()函数直接继承基类的函数

        self.hungry=True

def eat(self):

if self.hungry:

            print("no eat")

类组合

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 条！" % (self.turtle.num, self.fish.num))

BIF...

1,判断是否为子类   issubclass（子类，基类）

>>> class B():

    pass

>>> class A(B):

    pass

>>> issubclass(A,B)

True

>>>

2.isinstance（实例对象，类）判断对象是否属于类

>>> class A:

    pass

>>> a=A()

>>> isinstance(a,A)

True

>>>

3.property（）便于后期维护

>>> class A():

    def __init__(self,size=100):

        self.size=size

    def myname(self):

        return self.size

    def hername(self):

        return self.size

    def hisname(self):

        return self.size

    x=property(myname,hername,hisname)

>>> a=A()

>>> a.myname()

100

>>> a.x

100