property，类方法和静态方法

# from math import pi
#
# class Circle:
#     def __init__(self, r):
#         self.r = r
#
#     @property
#     def perimeter(self):
#         return 2*pi*self.r
#
#     @property
#     def area(self):
#         return self.r**2*pi
#
# circle = Circle(4)
# print(circle.perimeter)
# print(circle.area)
 
# class Person:
#     discount = 0.8
#     def __init__(self, name):
#         self.__name = name
#         self.price = 20
#
#     @property
#     def name(self):
#         return self.__name
#
#     @name.deleter
#     def name(self):
#         return self.__name
#
#     @name.setter
#     def name(self, new_name):
#         self.__name = new_name
#
# person = Person('aaa')
# print(person.name)
# person.name = 'bbb'
# del person.name
# print(person.name)
 
class Person:
    age = 1
    def __init__(self, name):
        self.__name = name
 
    @property                # 把方法变成属性
    def name(self):
        return self.__name
 
    @classmethod            # 把方法变成类方法，这个方法就直接可以被类调用，不需要依托任何对象
    def get_age(cls, age):
        cls.age = age
 
# 如果一个函数 既和对象没有关系 也和类没有关系 那么就用staticmethod将这个函数变成静态方法
    @staticmethod
    def get_usr_pwd():
        usr = input('input user:')
        pwd = input('input password')
        print('user is %s, password is %s' %(usr, pwd))
 
person = Person('aaa')
print(person.name)
Person.get_age(54)
Person.get_usr_pwd()