dictionary that discards old items

[Michael Hoffman]

Will McGugan wrote:

> I need a collection class that behaves like a dictionary but when it 
> reaches 'n' items it discards the oldest item so that the length never 
> goes above 'n'. (Its for caching search results)
> 
> I have a vague memory of a module that does this, but I cant remember 
> where I read about it. Can anyone enlighten me?

You want a Least Recently Used, or LRU, cache. Here's one:

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/252524

Google for <LRU python> to find others.
-- 
Michael Hoffman