python基础学习1-描述符

#!/usr/bin/env python
# -*- coding:utf-8 -*-
#描述符就是将某种特殊类型的类的实例指派给另一个类的属性
#特殊类型指 实现了
# __get__(self,instance,owner),
# __set__(self,instance,value),
# __delete__(self,instance)三个方法中至少一个

class MyDecriptor: #描述符类
    def __get__(self, instance, owner):
        print("__get__",self, instance, owner)
    def __set__(self, instance, value):
        print("__set__",self, instance, value)
    def __delete__(self, instance):
        print("__delete__",self, instance)

class Test:
    x=MyDecriptor()
t1= Test()
print(t1.x)
t1.x="x-man"

#=====》实例温度转换  根据设置的摄氏度换算出华氏度

class Celsius:
    def __init__(self,value=26):
        self.value=value

    def __get__(self, instance, owner):
        return  self.value
    def __set__(self, instance, value):
        self.value = value


class Fahrenheit:

    def __get__(self, instance, owner):
        return  instance.cel*1.8+32
    def __set__(self, instance, value):
        instance.cel=(float)(value-32)/1.8


class Temperature:  #温度类的两个属性分别设置的摄氏度标识符类和华氏度标识符类
    cel=Celsius(30)
    fah=Fahrenheit()

tem = Temperature()
print(tem.cel)
print(tem.fah)