Wrote a memoize function: I do not mind feedback

Cecil Westerhof Cecil at decebal.nl
Wed Apr 29 10:04:21 CEST 2015


Op Wednesday 29 Apr 2015 09:02 CEST schreef Ian Kelly:

> On Wed, Apr 29, 2015 at 12:06 AM, Cecil Westerhof <Cecil at decebal.nl> wrote:
>> Op Monday 27 Apr 2015 22:35 CEST schreef Albert-Jan Roskam:
>>> def some_func(arg, _memoize={}):
>>> try:
>>> return _memoize[arg]
>>> except KeyError:
>>> result = some_expensive_operation(arg)
>>> _memoize[arg] = result
>>> return result
>>
>> That is in a way the same as what I do, except I do not use an
>> exception. Iunderstand it is not as expensive as it was anymore,
>> but I do not like to use an exception (when not necessary).
>
> It's useful to keep in mind which case it is that you're trying to
> optimize. The expensive case for exceptions is when one actually
> gets raised. A try that doesn't raise an exception is pretty cheap,
> probably cheaper than looking up the key in the dict twice as the
> code you linked does. Compare:

It is not only performance wise, I find the code without the try also
better looking. But that is very personally I suppose.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof



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