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Date: Mon, 18 Apr 2011 11:09:29 +1200
From: Greg Ewing <greg.ewing@canterbury.ac.nz>
Subject: Re: Feature suggestion -- return if true
In-reply-to: <20110417083347.0acf21e5.darcy@druid.net>
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D'Arcy J.M. Cain wrote:
> On Sun, 17 Apr 2011 16:21:53 +1200
> Gregory Ewing <greg.ewing@canterbury.ac.nz> wrote:
> 
>>   def get_from_cache(x):
>>     y = cache.get(x)
>>     if not y:
>>       y = compute_from(x)
>>       cache[x] = y
>>     return y
> 
> I prefer not to create and destroy objects needlessly.

How does that create objects needlessly?

>  def get_from_cache(x):
>    if not x in cache:
>      cache[x] = compute_from(x)
>    return cache[x]

That looks up the cache *twice* for every access. Mine
only does one lookup when the item is already in the
cache.

-- 
Greg