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Re: Wrote a memoize function: I do not mind feedback

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

> On Wed, Apr 29, 2015 at 12:06 AM, Cecil Westerhof <Cecil@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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Wrote a memoize function: I do not mind feedback Cecil Westerhof <Cecil@decebal.nl> - 2015-04-27 15:35 +0200
  Re: Wrote a memoize function: I do not mind feedback Peter Otten <__peter__@web.de> - 2015-04-27 16:28 +0200
  Re: Wrote a memoize function: I do not mind feedback Albert-Jan Roskam <fomcl@yahoo.com> - 2015-04-27 20:35 +0000
    Re: Wrote a memoize function: I do not mind feedback Cecil Westerhof <Cecil@decebal.nl> - 2015-04-29 08:06 +0200
      Re: Wrote a memoize function: I do not mind feedback Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-29 01:02 -0600
        Re: Wrote a memoize function: I do not mind feedback Cecil Westerhof <Cecil@decebal.nl> - 2015-04-29 10:04 +0200
          Re: Wrote a memoize function: I do not mind feedback Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-04-29 09:58 +0100
            Re: Wrote a memoize function: I do not mind feedback Cecil Westerhof <Cecil@decebal.nl> - 2015-04-29 13:52 +0200

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