python-面向对象——继承

继承

#encoding:utf-8
class Animal:
    def eat(self):
        print("吃吃吃")
    def drink(self):
        print("喝喝喝")
    def sleep(self):
        print("睡觉")
    def run(self):
        print("跑")

class Dog(Animal):
    def bark(self):
        print("汪汪汪")
class Cat(Animal):
    def catch(self):
        print("捉老鼠")

wangcai = Dog()
wangcai.eat()
wangcai.bark()
mimi = Cat()
mimi.run()
mimi.catch()
运行结果：
吃吃吃
汪汪汪
跑
捉老鼠

可以多层继承，子类可以直接调用父类的父类的函数

class Animal:
    def eat(self):
        print("吃吃吃")
    def drink(self):
        print("喝喝喝")
    def sleep(self):
        print("睡觉")
    def run(self):
        print("跑")

class Dog(Animal):
    def bark(self):
        print("汪汪汪")
class xiaotq(Dog):
    def fly(self):
        print("-------飞-----")
xiaotq = xiaotq()
xiaotq.fly()
xiaotq.eat()
xiaotq.bark()

重写

#encoding:utf-8
class Animal:
    def eat(self):
        print("吃吃吃")
    def drink(self):
        print("喝喝喝")
    def sleep(self):
        print("睡觉")
    def run(self):
        print("跑")

class Dog(Animal):
    def bark(self):
        print("汪汪汪")

class xiaotq(Dog):
    def fly(self):
        print("-------飞-----")
#方法的重写，名字必须与父类一样
    def bark(self):
        print("++=狂叫+++")

xiaotq = xiaotq()
xiaotq.fly()
xiaotq.eat()
xiaotq.bark()
运行结果：
-------飞-----
吃吃吃
++=狂叫+++

调用被重写的方法：

#encoding:utf-8
class Animal:
    def eat(self):
        print("吃吃吃")
    def drink(self):
        print("喝喝喝")
    def sleep(self):
        print("睡觉")
    def run(self):
        print("跑")

class Dog(Animal):
    def bark(self):
        print("汪汪汪")
class xiaotq(Dog):
    def fly(self):
        print("-------飞-----")
    def bark(self):
        print("++++狂叫+++")
#调用被重写的父类的方法：
        Dog.bark(self) #方法一
        super().bark() #方法二
    
xiaotq = xiaotq()
xiaotq.fly()
xiaotq.eat()
xiaotq.bark()

多继承

python支持多继承

class Base(object):
    def test(self):
        print("======Base====")
class A(Base):
    def test1(self):
        print("test1--------")
class B(Base):
    def test2(self):
        print("test2=======")
class C(A,B):
    pass
c = C()
c.test1()
c.test2()
c.test()
运行结果：
test1--------
test2=======
======Base====

class Base(object):
    def test(self):
        print("======Base====")
class A(Base):
    def test(self):
        print("test1--------")
class B(Base):
    def test(self):
        print("test2=======")
class C(A,B):
    def test(self):
        print("cccccccccc=======")
c = C()
c.test()
print(C.__mro__)  #调用方法时的搜索顺序，如果在某个类中找到了方法，就停止搜索
运行结果：
cccccccccc=======
(<class '__main__.C'>, <class '__main__.A'>, <class '__main__.B'>, <class '__main__.Base'>, <class 'object'>)

所以，设计类时，要尽量避免出现相同的类名