Python3 系列之 面向对象篇

面向对象的三大特性：继承、封装和多态

Python 做到胶水语言，当然也支持面向对象的编程模式。

封装

class UserInfo(object):
    lv = 5

    def __init__(self, name, age, account):
        self.name = name
        self._age = age
        self.__account = account

    def get_account(self):
        return self.__account

    @classmethod
    def get_name(cls):
        return cls.lv

    @property
    def get_age(self):
        return self._age

if __name__ == "__main__":
    userinfo = UserInfo("hippie", 26, 123456)
    print(dir(userinfo))
    print(userinfo.__dict__)
    print(userinfo._age)
    print(userinfo.get_account())
    print(userinfo._UserInfo__account)
    print(UserInfo.lv)
    print(userinfo.get_age)

继承

class UserInfo(object):
    lv = 5

    def __init__(self, name, age, account):
        self.name = name
        self._age = age
        self.__account = account

    @property
    def get_account(self):
        return self.__account

class UserInfo2(UserInfo):

    @property
    def get_account(self):
        return super().get_account + 10

if __name__ == "__main__":
    a = UserInfo("hippie", 26, 123456)
    print(a.get_account)

    b = UserInfo2("hippie", 26, 123456)
    print(b.get_account)

    print(isinstance(a, UserInfo))
    print(isinstance(a, UserInfo2))

多态

class User(object):
    def __init__(self, name):
        self.name = name

    def printUser(self):
        print(self.name)

class UserVip(User):
    def printUser(self):
        print("Hello VIP:" + self.name)

class UserGeneral(User):
    def printUser(self):
        print("Hello User:" + self.name)

if __name__ == "__main__":
    vip = UserVip("hippie")
    vip.printUser()

    vip = UserGeneral("jock")
    vip.printUser()

总结

封装、继承和多态是面向对象中的重要思想，对于 Python 这种高级语言，虽然很多地方从语法上可以不用面向对象的思想，但是对于项目构建来说，面向对象是基本要求，这样做显然是很有必要的。

相关参考

• Python 入门教程：【草根学 Python （基于Python3.6）】