property用法

用法一

class Test(object):
    def __init__(self):
        self.__Num = 100

    def setNum(self,Num):
        print("---set---")
        self.__Num = Num

    def getNum(self):
        return self.__Num

    num = property(getNum,setNum)

t = Test()
print("##########1")
print(t.num)　　#相当于调用了t.getNum()
print("##########2")
t.num = 200　　 #相当于调用了t.setNum(200)
print("##########3")
print(t.num)
print("##########4")

　　输出

##########1
100
##########2
---set---
##########3
200
##########4

　　

用法二

class Test(object):
    def __init__(self):
        self.__Num = 100

    @property
    def num(self):
        return self.__Num

    @num.setter
    def num(self,Num):
        print("---set---")
        self.__Num = Num

t = Test()
print("##########1")
print(t.num)
print("##########2")
t.num = 200
print("##########3")
print(t.num)
print("##########4")

　　输出

##########1
100
##########2
---set---
##########3
200
##########4