一、封装

 1、封装指的就是把数据与功能都整合到一起

2、在封装的基础上,我可以将装到对象或者类中的属性给隐藏起来
  注意:
  (1)在定义类或者初始化对象时,在属性前加__,就会将该属性隐藏起来
  但该隐藏起始只是一种变形_类名__属性名,并没有真的隐藏起
  (2)该变形操作是在类定义阶段扫描语法时发生的变形,类定义之后添加的__开头的属性不会发生变形
  (3)该隐藏是对外不对内
  (4) 在继承中,父类如果不想让子类覆盖自己的方法,可以将方法定义为私有的???
# 例1
# class Student:
#     __school = "oldboy"  # _Student__school = "oldboy"
#
#     def __init__(obj, x, y, z):
#         obj.__name = x  # obj._Student__name = x
#         obj.age = y
#         obj.gender = z
#
#     def __choose(self):  # obj._Student__choose
#         print("%s 正在选课" %self.name)
#
#
# stu_obj1 = Student("冯疯子", 18, "female")
# stu_obj1.__x=111
# print(stu_obj1.__dict__)
# print(stu_obj1.__x)

# print(stu_obj1.__dict__)
# print(stu_obj1._Student__name)

# print(Student.__dict__)
# print(Student._Student__school)
# print(stu_obj1._Student__school)
隐藏属性的意义
1、把数据属性隐藏起来的意义是:在类内开放接口,让外界使用者通过接口来操作属性值,我们可以在接口之上附加任意的逻辑
  来严格控制外界使用者对属性的操作
# class Student:
#     __school = "oldboy"  # _Student__school = "oldboy"
#
#     def __init__(obj, x, y, z):
#         obj.__name = x  # obj._Student__name = x
#         obj.__age = y
#         obj.gender = z
#
#     def __choose(self):  # obj._Student__choose
#         print("%s 正在选课" % self.name)
#
#     def get_name(self):
#         print(self.__name)  # print(self._Student__name)
#
#     def set_age(self,x):
#         if type(x) is not int:
#             print("年龄必须是整型,傻叉")
#             return
#         self.__age = x
#
#     def get_age(self):
#         print(self.__age)
#
#     def del_age(self):
#         del self.__age
#
# stu_obj1 = Student("冯疯子", 18, "female")
# # stu_obj1.get_name()
#
#
# # stu_obj1.set_age("asfdasfdasfafd")
# stu_obj1.set_age(19)
# stu_obj1.get_age()
# # print(stu_obj1.__dict__)
2、把功能属性隐藏起来:隔离复杂度
# class ATM:
#     def __card(self):
#         print('插卡')
#     def __auth(self):
#         print('用户认证')
#     def __input(self):
#         print('输入取款金额')
#     def __print_bill(self):
#         print('打印账单')
#     def __take_money(self):
#         print('取款')
#
#     def withdraw(self):
#         self.__card()
#         self.__auth()
#         self.__input()
#         self.__print_bill()
#         self.__take_money()
#
# a=ATM()
# a.withdraw()

二、装饰器

  1、 property

# 例1
# class People:
#     def __init__(self, name, height, weight):
#         self.name = name
#         self.height = height
#         self.weight = weight
#
#     @property
#     def bmi(self):
#         return self.weight / (self.height ** 2)
#
#
# p = People('egon', 1.81, 70)
# p.height = 1.84
# print(p.bmi())

 

# 例2
# class Student:
#     __school = "oldboy"  # _Student__school = "oldboy"
#
#     def __init__(obj, x, y, z):
#         obj.__name = x
#         obj.__age = y
#         obj.gender = z
#
#     def get_name(self):
#         print("访问控制")
#         return self.__name
#
#     def set_name(self,x):
#         print("赋值控制")
#         self.__name = x
#
#     def del_name(self):
#         print("删除控制")
#         del self.__name
#
#     def get_age(self):
#         return self.__age
#
#     def set_age(self, x):
#         if type(x) is not int:
#             print("年龄必须是整型,傻叉")
#             return
#         self.__age = x
#
#     def del_age(self):
#         print("不让删")
#
#
#     age = property(get_age, set_age, del_age)
#     name = property(get_name, set_name, del_name)
#
#
# stu_obj1 = Student("冯疯子", 18, "female")
#
# # print(stu_obj1.age)
# # stu_obj1.age = "19"
# # del stu_obj1.age
# # print(stu_obj1.age)
#
#
# print(stu_obj1.name)
# # stu_obj1.name="EGON"
# # del stu_obj1.name

 

# 例3:
class Student:
    __school = "oldboy"  # _Student__school = "oldboy"

    def __init__(obj, x, y, z):
        obj.__name = x
        obj.__age = y
        obj.gender = z

    @property
    def name(self):
        print("访问控制")
        return self.__name

    @name.setter
    def name(self, x):
        print("赋值控制")
        self.__name = x

    @name.deleter
    def name(self):
        print("删除控制")
        del self.__name


stu_obj1 = Student("冯疯子", 18, "female")

stu_obj1.name

 

2、绑定与非绑定

类中的定义的函数
--- 绑定方法:谁来调用就会将谁当作第一个参数传入
(1)绑定给对象的方法:类中定义的函数默认就是绑定给对象的方法,应该是由对象调用,会把对象当作第一个参数传入
(2)绑定给类的方法:在类中的函数上加一个装饰器@classmethod,该函数就绑定给类了,应该是由类来调用,会把类当作第一个参数传入

---非绑定方法:既不与类绑定也不与对象绑定,就是一个普通的函数,谁都可以来调用,没有自动传参的效果,
在函数上添加装饰器@staticmethod
# class People:
#     def __init__(self, name, age):
#         self.name = name
#         self.age = age
#
#     def tell_info(self):
#         print("<%s:%s>" % (self.name, self.age))
#
#     @classmethod
#     def f1(cls):
#         print(cls)
#
#     @staticmethod
#     def f2(x,y,z):
#         print(x,y,z)
#
#
# p1=People('egon',18)
# # p1.tell_info()
#
# # print(p1.tell_info)
# # print(People.f1)
#
# # People.f1()
#
# # print(p1.f2)
# # print(People.f2)
# p1.f2(1,2,3)
# People.f2(1,2,3)

 

# 例1
import uuid
import settings
##sttings里的内容: IP='106.78.13' PORT=3306
class MySQL: def __init__(self,ip,port): self.mid = self.__create_id() self.ip = ip self.port = port def tell_info(self): print("%s:<%s:%s>" %(self.mid,self.ip,self.port)) @staticmethod def __create_id(): return uuid.uuid4() @classmethod def from_conf(cls): return cls(settings.IP, settings.PORT) # obj = MySQL("10.10.11.11",3306) # obj.tell_info() obj1=MySQL.from_conf() obj1.tell_info()

 

内容来源于网络如有侵权请私信删除

文章来源: 博客园

原文链接: https://www.cnblogs.com/guojieying/p/13441975.html

你还没有登录,请先登录注册
  • 还没有人评论,欢迎说说您的想法!