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面向对象特性—继承与接口(三十)

时间:2019-03-02 10:46:23      阅读:164      评论:0      收藏:0      [点我收藏+]

标签:info   object   method   abstract   顺序   面向对象   abs   main   解析   

 

import abc

class AllFile(metaclass=abc.ABCMeta):
    @abc.abstractmethod
    def read(self):
        pass
    # 父类定义抽象的方法,子类必须实现
    @abc.abstractmethod
    def write(self):
        pass

class Txt(AllFile):
    def read(self):
        print("txt read")
    def write(self):
        print("txt write")

class Mem(AllFile):
    def read(self):
        print("mem read")
    def write(self):
        print("mem write")

m = Mem()
m.read()
m.write()

 

继承顺序:

Java ,C#只能继承一个类,Python可以继承多个类

技术图片

class A:
    def test(self):
        print("this is A")

class B(A):
    # def test(self):
    #     print("this is B")
    pass

class D(B):
    # def test(self):
    #     print("this is D")
    pass

class C(A):
    # def test(self):
    #     print("this is C")
    pass

class E(C):
    # def test(self):
    #     print("this is E")
    pass

class F(D,E):
    # def test(self):
    #     print("this is F")
    pass

print(F.__mro__)
‘‘‘
F.__mro__ 揭秘了F的继承顺序
(<class ‘__main__.F‘>, <class ‘__main__.D‘>, <class ‘__main__.B‘>, 
<class ‘__main__.E‘>, <class ‘__main__.C‘>, <class ‘__main__.A‘>, <class ‘object‘>)
‘‘‘
f = F()
f.test() # F-->D-->B-->E-->C-->A

Python会计算一个方法解析顺序(MRO) 列表,这个列表就是一个简单的所有基类的线性顺序表

注意:Python2 与Python3 中的继承顺序是不一样的

 

子类中调用父类的方法

class Vehicle:
    Country = "China"
    def __init__(self,name,speed,load,power):
        self.Name = name
        self.Speed = speed
        self.Load = load
        self.Power = power

    def run(self):
        print("running...")

class Subway(Vehicle):
    def __init__(self,name,speed,load,power,line):
        Vehicle.__init__(self,name,speed,load,power)
        self.Line = line

    def show_info(self):
        print("%s %d号线" %(self.Name,self.Line))

    def run(self):
        Vehicle.run(self)
        print("%s %d号线,以%s的速度在运行" %(self.Name,self.Line,self.Speed))

line3 = Subway("深圳地铁","100km/s",10000,"",3)
line3.show_info()
line3.run()
‘‘‘
深圳地铁 3号线
running...
深圳地铁 3号线,以100km/s的速度在运行
‘‘‘

 

super调用父类的方法

class Vehicle:
    Country = "China"
    def __init__(self,name,speed,load,power):
        self.Name = name
        self.Speed = speed
        self.Load = load
        self.Power = power

    def run(self):
        print("running...")

class Subway(Vehicle):
    def __init__(self,name,speed,load,power,line):
        # Vehicle.__init__(self,name,speed,load,power)
        super().__init__(name,speed,load,power)
        self.Line = line

    def show_info(self):
        print("%s %d号线" %(self.Name,self.Line))

    def run(self):
        # Vehicle.run(self)
        super().run()
        print("%s %d号线,以%s的速度在运行" %(self.Name,self.Line,self.Speed))

line3 = Subway("深圳地铁","100km/s",10000,"",3)
line3.show_info()
line3.run()
‘‘‘
深圳地铁 3号线
running...
深圳地铁 3号线,以100km/s的速度在运行
‘‘‘

 

面向对象特性—继承与接口(三十)

标签:info   object   method   abstract   顺序   面向对象   abs   main   解析   

原文地址:https://www.cnblogs.com/xiangtingshen/p/10459741.html

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