小编And*_*rei的帖子

为了说明问题,我创建了一个简单的例子:

#!/usr/bin/env python

class Person():
    def __init__(self):
        self.cache = {}

    def get_person_age(self):
        def get_age():
            print "Calculating age..."
            return self.age
        print self.cache
        return self.cache.setdefault(self.name, get_age())

    def set_person(self, name, age):
        self.name = name
        self.age = age


p = Person()
p.set_person('andrei', 12)

for k in range(0, 5):
    p.get_person_age()

我希望一旦设置了缓存,就不会再次调用函数get_person_age,但事实并非如此:

$ python cache_test.py 
{}
Calculating age...
{'andrei': 12}
Calculating age...
{'andrei': 12}
Calculating age...
{'andrei': 12}
Calculating age...
{'andrei': 12}
Calculating age...

一次又一次地调用函数.怎么了？