Feature suggestion -- return if true

Greg Ewing greg.ewing at canterbury.ac.nz
Mon Apr 18 01:09:29 CEST 2011


D'Arcy J.M. Cain wrote:
> On Sun, 17 Apr 2011 16:21:53 +1200
> Gregory Ewing <greg.ewing at 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



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