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  • 继承

    今日内容大纲

    1. 初识继承

    字面意思:儿子完全可以使用父类的所有内容

    专业角度: 如果 B类继承 A类,B 类就称为子类,派生类

    A类就称为父类,基类,超类

    面向对象的三大特性之一:继承,封装,多态

    2.继承的优点

    1.减少代码的重复性

    2.增加类之间的耦合性

    3.代码更加清晰,流畅

    3.单继承

    1.类名执行父类属性方法

    2.对象执行父类属性方法

    3.在子类中既执行子类方法又执行父类方法

    class Animal:
    
    #
    
    #     def __init__(self, name, sex, age):
    
    #
    
    #         self.name = name
    
    #         self.age = age
    
    #         self.sex = sex
    
    #
    
    #
    
    # class Human(Animal):
    
    #     pass
    
    
    
    
    
    # class Dog(Animal):
    
    #     pass
    
    #
    
    #
    
    # class Cat(Animal):
    
    #     pass
    
    
    
    
    
    # class Cat(object):
    
    #     pass
    cat1 = Cat()
    # Human,Dog,Cat 子类,派生类.
    # Animal 父类,基类,超类.
    
    # person = Human('李业', '男', 18)
    # print(person.name)
    
    

    4.多继承

    1.经典类:不继承 object 类,深度优先原则

    2.新式类:继承 object 类.mro(c3)算法

    class A(object):
    
    #     pass
    
    
    
    
    
    
    
    # class A:
    
    #     pass
    
    #
    
    #
    
    # class B(A):
    
    #     pass
    
    #
    
    # class C(B):
    
    #     pass
    
    
    
    
    
    # class A:
    
    #     pass
    
    #
    
    #
    
    # class B(object):
    
    #     pass
    
     class ShenXian:
    
    #
    
    #     def fly(self):
    
    #         print('神仙都会飞')
    
    #
    
    #     def walk(self):
    
    #         print('神仙会走路')
    
    #
    
    # class Monkey:
    
    #
    
    #     def climb(self):
    
    #         print('猴子都会爬树')
    
    #
    
    #     def walk(self):
    
    #         print('猴子会走路')
    
    #
    
    # class SunWuKong(ShenXian,Monkey):
    
    #     pass
    
    #
    
    # sun = SunWuKong()
    
    # # sun.fly()
    
    # # sun.climb()
    # sun.walk()
    
    # 经典类: 深度优先.从左至右,深度优先.
    
    class O:
    
        name = '太白'
    
    
    
    class D(O):
    
        pass
    
    
    
    class E(O):
    
        name = '李业'
    
        # pass
    
    class F(O):
    
        name = '宝元'
    
    
    
    class B(D,E):
    
        pass
    
    
    
    class C(E,F):
    
        pass
    
    
    
    class A(B,C):
    
        pass
    
    obj = A()
    
    print(obj.name)
    
    
    
    # mro(Child(Base1,Base2)) = [ Child ] + merge( mro(Base1), mro(Base2), [ Base1, Base2] )
    
    # mro(A(B,C)) = [A] + merge(mro(B),mro(C),[B,C])
    
    
    
    '''
    
    mro(A(B,C)) = [A] + merge(mro(B),mro(C),[B,C])
    
    
    
    mro(B(D,E)) = [B] + merge(mro(D),mro(E),[D,E])
    
    
    
    mro(B(D,E)) = [B] + merge([D,O],[E,O],[D,E])
    
    mro(B(D,E)) = [B,D] + merge([O],[E,O],[E])
    
    mro(B(D,E)) = [B,D,E] + merge([O],[O])
    
    mro(B(D,E)) = [B,D,E,O]
    
    
    
    mro(C) = [C,E,F,O]
    
    
    
    mro(A(B,C)) = [A] + merge([B,D,E,O],[C,E,F,O],[B,C])
    
                = [A,B] + merge([D,E,O],[C,E,F,O],[C])
    
                = [A,B,D] + merge([E,O],[C,E,F,O],[C])
    
                = [A,B,D,C] + merge([E,O],[E,F,O])
    
                = [A,B,D,C,E] + merge([O],[F,O])
    
                = [A,B,D,C,E,F,O] 
    
               
    
    
    
    '''
    # print(A.mro())
    
    单继承课堂练习
    class Base:
        def __init__(self, num):
            self.num = num
        def func1(self):
            print(self.num)
    
    class Foo(Base):
        pass
    obj = Foo(123)  # 实例化一个对象
    obj.func1()    # Foo 里找不到就去父类找  
    #  123
    
    class Base:
        def __init__(self, num):
            self.num = num
    
        def func1(self):
            print(self.num)
    
    class Foo(Base):
    
        def func1(self):
            print("Foo. func1", self.num)
    
    obj = Foo(123)
    print(obj.__dict__)
    # obj.func1()
    # {'num': 123}
    # Foo. func1 123
    
    class Base:
        def __init__(self, num):
            self.num = num
        def func1(self):
            print(self.num)
    class Foo(Base):
        def func1(self):
            print("Foo. func1", self.num)
    obj = Foo(123)
    obj.func1()
    #  Foo. func1 123
    
    class Base:
    #
        def __init__(self, num):
            self.num = num
    
        def func1(self):  # self= obj
            print(self.num)  # 123
            self.func2()  # obj.func2()
    
        def func2(self):
            print("Base.func2")
    
    class Foo(Base):
        def func2(self):
            print("Foo.func2")
    
    obj = Foo(123)
    obj.func1()
    123
    Foo.func2
    
    class Base:
        def __init__(self, num):
            self.num = num
    
        def func1(self):
            print(self.num)
            self.func2()
    
        def func2(self):
            print(111, self.num)
    
    class Foo(Base):
        def func2(self):
            print(222, self.num)
    lst = [Base(1), Base(2), Foo(3)]
    
    for obj in lst:
        obj.func2()
    111 1
    111 2
    222 3
    
    class Base:
    #     def __init__(self, num):
    #         self.num = num
    #
    #     def func1(self):  # self = Foo(3)
    #         print(self.num)
    #         self.func2()
    #
    #     def func2(self):
    #         print(111, self.num)
    #
    # class Foo(Base):
    #     def func2(self):
    #         print(222, self.num)
    #
    # lst = [Base(1), Base(2), Foo(3)]
    #
    # for obj in lst:
    #     obj.func1()
    
    
    1
    111 1
    2
    111 2
    3
    222 3
    
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  • 原文地址:https://www.cnblogs.com/hualibokeyuan/p/11330868.html
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