Python2的function cache实现

今天看到Python3中有lru_cache的function cache，无聊就试着在Python2.7中实现了一个简单的版本：

#!env python#coding=utf-8# # Author:       [e-mail]# # Created Time: 2017年05月28日 星期日 09时34分06秒# # FileName:     test_decorator_cache.py# # Description:  # # ChangeLog:from functools import wrapsfrom collections import OrderedDictdef cache(maxsize = 10):    def cache_decorator(fn):        _cache = OrderedDict()        @wraps(fn)        def inner(*args, **kwargs):            if args in _cache:                print 'hit cache!'                return _cache.get(args)            r = fn(*args, **kwargs)            if len(_cache) >= maxsize:                _key = _cache.keys()[0]                del _cache[_key]                print 'queue is full, del _cache[%s]' % (_key)            return _cache.setdefault(args, r)        return inner    return cache_decorator@cache(maxsize = 2)def fn(i):    print 'get fn(%d).' % (i)    return i*iprint fn(11)print fn(13)print fn(11)print fn(15)print fn(11)print fn(13)

输出如下：

get fn(11).
121
get fn(13).
169
hit cache!
121
get fn(15).
queue is full, del _cache[11]
225
get fn(11).
queue is full, del _cache[13]
121
get fn(13).
queue is full, del _cache[15]
169