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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 python2.6.5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | class Cat(object):
def __init__(self,food):
self.food=food
def eat(self):
return self.food
def say(self):
if 'im_func' in dir(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：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | class Cat(object):
def __init__(self,food):
self.food=food
@property
def eat(self):
return self.food
def say(self):
if 'im_func' in dir(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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | #!/usr/bin/python
#-*-utf-8-*-
class Cat(object):
def __init__(self,food):
self.food=food
@property
def eat(self):
return self.food
def say(self):
if 'im_func' in dir(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?"
print tim.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?
现在我们把装饰器@property加上去
输出：
Miao...,I want to eat fish!
^^,Fish is so nice
可能这个例子也不是很适合解释这个例子，不过应该还是蛮生动的吧
从网上了解到，用@property装饰成的属性在2.6无法赋值
为了过渡期的兼容性，需要我们自己来配置setter
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | #!/usr/bin/python
#-*-utf-8-*-
class C(object):
def __init__(self,x):
self.__x=x
@property
def foo(self):
return self.__x
@foo.setter
def foo(self,value):
self.__x=value
@foo.deleter
def foo(self):
del self.__x
if __name__ == "__main__":
c=C(10)
print c.foo
c.foo=12
print c.foo
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10
12
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