一、使用方法，封装变量.
1 # 使用方法，封装变量.
2 class Wife:
3 def __init__(self, name, age, weight):
4 self.name = name
5 # 本质:障眼法(实际将变量名改为：_类名__age)
6 # self.__age = age
7 self.set_age(age)
8 # self.__weight = weight
9 self.set_weight(weight)
10
11 # 提供公开的读写方法
12 def get_age(self):
13 return self.__age
14
15 def set_age(self, value):
16 if 21 <= value <= 31:
17 self.__age = value
18 else:
19 raise ValueError("我不要")
20
21 # 提供公开的读写方法
22 def get_weight(self):
23 return self.__weight
24
25 def set_weight(self, value):
26 if 40 <= value <= 60:
27 self.__weight = value
28 else:
29 raise ValueError("我不要")
30
31 """
32 w01 = Wife("铁锤公主", 87, 87)
33 # 重新创建了新实例变量(没有改变类中定义的__age)
34 # w01.__age = 107
35 w01._Wife__age = 107 # (修改了类中定义的私有变量)
36
37 print(w01.__dict__)# python内置变量,存储对象的实例变量.
38 """
39
40 w01 = Wife("铁锤公主", 30, 50)
41 w01.set_age(25)
42 w01.set_weight(55)
43 print(w01.get_age())
44 print(w01.get_weight())
二、使用property(读取方法，写入方法)对象,封装变量.
1 """
2 使用property(读取方法，写入方法)对象,封装变量.
3 """
4 class Wife:
5 def __init__(self, name, age, weight):
6 self.name = name
7 # self.set_age(age)
8 self.age = age
9 # self.set_weight(weight)
10 self.weight = weight
11
12 def get_age(self):
13 return self.__age
14
15 def set_age(self, value):
16 if 21 <= value <= 31:
17 self.__age = value
18 else:
19 raise ValueError("我不要")
20
21 # 属性 property对象拦截对age类变量的读写操作
22 age = property(get_age,set_age)
23
24 def get_weight(self):
25 return self.__weight
26
27 def set_weight(self, value):
28 if 40 <= value <= 60:
29 self.__weight = value
30 else:
31 raise ValueError("我不要")
32
33 weight = property(get_weight,set_weight)
34
35 w01 = Wife("铁锤公主", 30, 50)
36 # w01.set_age(25)
37 w01.age = 25
38 print(w01.age)
39 w01.weight = 45
40 print(w01.weight)
三、使用标准属性,封装变量.
1 """
2 使用标准属性,封装变量.
3 """
4
5 class Wife:
6 def __init__(self, name, age, weight):
7 self.name = name
8 self.age = age
9 self.weight = weight
10
11 @property # 创建property对象，只负责拦截读取操作
12 def age(self):
13 return self.__age
14
15 @age.setter # 只负责拦截写入操作
16 def age(self, value):
17 if 21 <= value <= 31:
18 self.__age = value
19 else:
20 raise ValueError("我不要")
21
22 @property
23 def weight(self):
24 return self.__weight
25
26 @weight.setter
27 def weight(self, value):
28 if 40 <= value <= 60:
29 self.__weight = value
30 else:
31 raise ValueError("我不要")
32
33 w01 = Wife("铁锤公主", 30, 50)
34 w01.age = 25
35 print(w01.age)
36 w01.weight = 45
37 print(w01.weight)
四、属性内存图
五、封装设计思想（分而治之、变则疏之、高内聚、低耦合）
1 """
2 封装设计思想
3 需求：老张开车去东北
4 """
5
6
7 class Person:
8 def __init__(self, name):
9 self.name = name
10
11 @property
12 def name(self):
13 return self.__name
14
15 @name.setter
16 def name(self, value):
17 self.__name = value
18
19 def go_to(self, str_postion, type):
20 """
21 去
22 :param str_postion: 位置
23 :param type: 方式
24 """
25 print(self.name, "去", str_postion)
26 type.run(str_postion)
27
28
29 class Car:
30 def run(self, str_position):
31 """
32 行驶
33 :param str_position: 位置
34 """
35 print("汽车行驶到:", str_position)
36
37
38 lz = Person("老张")
39 car = Car()
40 # 老张开车去东北
41 lz.go_to("东北", car)
来源：https://www.cnblogs.com/libotao/p/12496955.html