python面向对象操作2（速通版）（上）-阿里云开发者社区

python面向对象操作2（速通版）（上）

2023-11-17 41

版权

本文内容由阿里云实名注册用户自发贡献，版权归原作者所有，阿里云开发者社区不拥有其著作权，亦不承担相应法律责任。具体规则请查看《阿里云开发者社区用户服务协议》和《阿里云开发者社区知识产权保护指引》。如果您发现本社区中有涉嫌抄袭的内容，填写侵权投诉表单进行举报，一经查实，本社区将立刻删除涉嫌侵权内容。

简介： python面向对象操作2（速通版）

一、私有和公有属性的定义和使用

1.公有属性定义和使用

公有属性会破坏封装性

class Account(object):
    def __init__(self,name,balance):
        self.name = name
        self.balance = balance
    def show_info(self):
        print(self.name + '有' + self.balance,"元")
jack = Account('JackMa',9999999)
print(jack.name)
print(jack.balance)
jack.name = '郭'
print(jack.name)
print(jack.balance)
class Account(object):
    def __init__(self,name,balance):
        self.name = name
        self.balance = balance
    def show_info(self):
        print(self.name + '有' + self.balance,"元")
jack = Account('JackMa',9999999)
print(jack.name)
print(jack.balance)
jack.name = '郭'
print(jack.name)
print(jack.balance)

2.私有属性

当一个类中的所有属性或方法，全是私有的时候，这个类时无意义的

class Account(object):
    def __init__(self,name,balance):
        self.__name = name
        self.__balance = balance
    def show_info(self):
        print(self.__name+'有',self.__balance,'元')
jack = Account('Jackma',99999999)
jack.show_info()

私有属性set和get方法

class Account(object):
    def __init__(self,name,balance):
        self.__name = name
        self.__balance = balance
    def show_info(self):
        print(self.__name+'有',self.__balance,'元')
    def get_name(self):
        return self.__name
    def set_balance(self,new_b):
        if isinstance(new_b,int):
            self.__balance = new_b
        else:
            print("不能存放阴间的钱")
    def get_balance(self):
        return self.__balance
jack = Account('Jackma',99999999)
jack.show_info()
jack.set_balance(1000)
m = jack.get_balance()
print(m)
m -= 999
print(m)

二、继承

1.应用

class Phone(object):
    def call(self,number):
        print(f'正在给{number}打电话')
class iPhone(Phone):
    def carmera(self):
        print("拍照")
iphonex = iPhone()
iphonex.call('128447873929')
iphonex.carmera()

2.子类不能用父类的私有方法

class Father(object):
    def __init__(self):
        self.__money = 999
        self.name = 'tom'
    def __show(self):
        print("这个是父类中的一个私有方法")
    def display(self):
        print("这个是父类中的一个私有方法")
class Son(Father):
    def play(self):
        print("这是子类中的方法")
        #子类不能用父类的私有方法
        self.__show()
s = Son()
s.play()
s.display()

3.子类初始化父类

class Father(object):
    def __init__(self,name):
        self.__money = 999
        self.name = name
class Son(Father):
    pass
#子类初始化父类的init
s = Son('tom')
print(s.name)

但子类有init方法会无法初始化父类

class Father(object):
    def __init__(self,name):
        self.__money = 999
        self.name = name
class Son(Father):
    def __init__(self,age):
        self.age = age
#子类初始化父类的init
s = Son('tom')
print(s.name)

解决办法就是手动init父类

4.子类重写和调用父类方法

class Father(object):
    def cure(self):
        print("父类")
class Son(Father):
    def cure(self):
        print("子类")
#子类初始化父类的init
s = Son()
s.cure()

class Father(object):
    def cure(self):
        print("父类")
class Son(Father):
    def cure(self):
        Father.cure(self)
        print("子类")
#子类初始化父类的init
s = Son()
s.cure()

5.多层继承

class A(object):
    def a(self):
        print('a function')
class B(A):
    def b(self):
        print('b function')
class C(B):
    def c(self):
        print('c function')
class D(C):
    def d(self):
        print('d function')
d = D()
d.a()
d.b()
d.c()
d.d()

方法重写

class A(object):
    def a(self):
        print('a function')
class B(A):
    def b(self):
        print('b function')
class C(B):
    #重写b
    def b(self):
        print('bc function')
    def c(self):
        print('c function')
class D(C):
    def d(self):
        print('d function')
d = D()
d.a()
d.b()
d.c()
d.d()

6.多层继承-初始化过程

class A(object):
    def __init__(self,a):
        self.a = a
class B(A):
    def __init__(self,a,b):
        A.__init__(self,a)
        self.b = b
class C(B):
    def __init__(self,a,b,c):
        B.__init__(self, a,b)
        self.c = c
class D(C):
    def __init__(self,a,b,c,d):
        C.__init__(self, a,b,c)
        self.d = d
d = D(1,2,3,4)
print(d.a,"  ",d.b,'    ',d.c,"  ",d.d)

7.多继承基本格式

class Father(object):
    def func_fa(self):
        print('Father Function')
class Mother(object):
    def func_mo(self):
        print('Mother function')
class Son(Father,Mother):
    def play(self):
        print('Son Play')
s = Son()
s.play()
s.func_mo()
s.func_fa()