python property内建函数的介绍
函数property的基本功能就是把类中的方法当作属性来访问，下面以一个有意思的例子介绍一下：
假如有一只猫，它忘了它喜欢吃什么，下面看看我们如何治好它吧
原代码： #运行环境 python2.7.10
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classCat(object):
def__init__(self,food):
self.food=food
defeat(self):
returnself.food
defsay(self):
if'im_func'indir(self.eat):
print"I forgot what to eat,Mybe %s"%self.food
else:
print"Miao...,I want to eat fish!"
if__name__=="__main__":
tim=Cat('Stone')
tim.say()
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运行后，这只猫说“I forgot what to eat,Mybe Stone”
看来是真有问题了
来个小改动吧：
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classCat(object):
def__init__(self,food):
self.food=food
@property
defeat(self):
returnself.food
defsay(self):
if'im_func'indir(self.eat):
print"I forgot what to eat,Mybe %s"%self.food
else:
print"Miao...,I want to eat fish!"
if__name__=="__main__":
tim=Cat('Stone')
tim.say()
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“Miao...,I want to eat fish!”
看来情况出在@property这个装饰器上
假如我们把@property去掉
在后边加一行代码
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#!/usr/bin/python
#-*-utf-8-*-
classCat(object):
def__init__(self,food):
self.food=food
@property
defeat(self):
returnself.food
defsay(self):
if'im_func'indir(self.eat):
print"I forgot what to eat,Mybe %s"%self.food
else:
print"Miao...,I want to eat fish!"
if__name__=="__main__":
tim=Cat('Stone')
tim.say()
try:
tim.eat="Is fish deliciout?"
printtim.eat
except:
print"^^,Fish is so nice"
<div>
</div>
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输出：
I forgot what to eat,Mybe Stone
Is fish deliciout?
输出：
Miao...,I want to eat fish!
^^,Fish is so nice
总结一下：加上了@property修饰的方法就变成了数据属性了，不再是方法了，如下：
class Cat(object):
def __init__(self,food):
self.food = food
#@property
def eat(self):
return self.food
def say(self):
print dir(self.eat)
if 'im_func' in dir(self.eat):
print "i forgot what to eat,maybe %s"%self.food
else:
print "meow..., I want to eat fish!"
if __name__ =='__main__':
tim = Cat('stone')
tim.say()
try:
tim.eat = "Is fish delicious?"
print tim.eat
except:
print '^^,fish is so nice!'
运行结果是：
meow..., I want to eat fish!
^^,fish is so nice!
如果是以下代码：
class Cat(object):
def __init__(self,food):
self.food = food
#@property
def eat(self):
return self.food
def say(self):
print dir(self.eat)
if 'im_func' in dir(self.eat):
print "i forgot what to eat,maybe %s"%self.food
else:
print "meow..., I want to eat fish!"
if __name__ =='__main__':
tim = Cat('stone')
tim.say()
try:
tim.eat = "Is fish delicious?"
print tim.eat
except:
print '^^,fish is so nice!'
运行结果是：
i forgot what to eat,maybe stone
Is fish delicious?
如果是以下代码：
class Cat(object):
def __init__(self,food):
self.food = food
@property
def eat(self):
return self.food
def say(self):
print dir(self.eat)
if 'im_func' in dir(self.eat):
print "i forgot what to eat,maybe %s"%self.food
else:
print "meow..., I want to eat fish!"
if __name__ =='__main__':
tim = Cat('stone')
tim.say()
try:
tim.eat1 = "Is fish delicious?"
print tim.eat1
except:
print '^^,fish is so nice!'
运行结果是：
meow..., I want to eat fish!
Is fish delicious?
在这里虽然ｔｉｍ．ｅａｔ已经不再是方法了，而是数据属性了，但是由于我们在主函数里面没有修改ｔｉｍ．ｅａｔ 而是修改了tim.eat1,所以得到的结果是上面的结果，呵呵
最主要的就是经过property修饰后函数不再是函数，方法不再是方法，而是数据属性了，