5 属性 property

1.属性  property

　调用私有属性通过实例方法调用。达到这种效果

#property的作用:相当于把方法进行了封装, 开发者在对属性设置数据的时候更方便

class Dog(object):
    def __init__(self):
        self.__num = 100
    def set_num(self,new_num):
        print("---setter")
        self.__num = new_num
    def get_num(self):
        print("----getter--")
        return self.__num

    num = property(get_num,set_num)    #通过属性实现这种效果

dog1 = Dog()
#print(dog1.get_num())
#dog1.set_num(50)
#print(dog1.get_num())

print("-"*50)
dog1.num = 111   #相当于调用了dog1.set_num(200)
print(dog1.num)   #相当于调用了dog1.get_num()

####  运行结果

---setter
----getter--
111

#注意点:
#t.num 到底是调用getNum()还是setNum(),要根据实际的场景来判断,
#1. 如果是给t.num赋值 那么一定调用setNum()
#2. 如果是获取t.num的值,那么就一定调用getNum()

2.@property

class Dog(object):
    def __init__(self):
        self.__num = 100

    @property
    def to_num(self):       #同名函数
        print("---getter")
        return self.__num

    @to_num.setter    #函数名.setter
    def to_num(self,new_num):  #同名函数
        print("---setter")
        self.__num = new_num


   # num = property(get_num,set_num)

dog1 = Dog()
dog1.to_num = 111   #相当于调用to_num(111)
print(dog1.to_num)   #相当于调用to_num()

---setter
---getter
111