Python3-2020-测试开发-20- 面向对象之封装，继承，多态

class Person:

    def __init__(self,name,age):

        self.name = name
        self.__age = age     # 私有属性

    
    def say_age(self):

        print("我的年龄"+self.__age)

    def say_name(self):

        print("我的姓名为："+self.name)



class Student(Person):

    def __init__(self,name,age,score):

        Person.__init__(self,name,age)
        self.score = score

    def say_name(self):
        """
        重写父类的方法
        :return:
        """
        print("重写后的，我的姓名为："+self.name)

s = Student("chu01","18",10)
s.say_age()




-----------------------
18

print(s.name)
# print(s.age)     ‘Student‘ object has no attribute ‘age‘,
print(s._Person__age)
-------------------
18

s.say_name()

----------------------
重写后的，我的姓名为：chu01

# 查看继承关系
print(Student.mro())    # <class ‘__main__.Student‘>, <class ‘__main__.Person‘>, <class ‘object‘>]

# 查看对象的所有的属性
print(dir(s))

----------------
[‘_Person__age‘, ‘__class__‘, ‘__delattr__‘, ‘__dict__‘, ‘__dir__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__init_subclass__‘, ‘__le__‘, ‘__lt__‘, ‘__module__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__setattr__‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘__weakref__‘, ‘name‘, ‘say_age‘, ‘say_name‘, ‘score‘]

# 重写object中的__str__()方法

print(s)    # <__main__.Student object at 0x1135ff7f0>

------------------
重写后
----------------------------------------------
 def __str__(self):

        return "11111"


print(s)   # 11111

"""

多个父类有相同的方法名称，那么多继承时候，继承哪个，可以使用mro()方法
"""

class A:

    def say(self):

        print("A")

class B:

    def say(self):

        print("B")

class C(B,A):

    def cc(self):

        print("cc")


c = C()
print(C.mro())
c.say()
-------------------------
[<class ‘__main__.C‘>, <class ‘__main__.B‘>, <class ‘__main__.A‘>, <class ‘object‘>]
B

"""多态"""

# 多态是指同一个方法调用由于对象不同可能产生不同的行为
# 1. 多态是方法的多态，属性没有多态
# 2. 多态存在有2和必要条件：继承，方法的重写


class Animal:

    def eat(self):

        print("动物在吃")


class Dog(Animal):

    def eat(self):

        print("狗在吃")

class Cat(Animal):

    def eat(self):

        print("猫在吃")

def enEat(m):

    if isinstance(m,Animal):

        m.eat()
    else:
        print("不能吃！")


enEat(Dog())
enEat(Cat())
enEat(Animal())

狗在吃
猫在吃
动物在吃