On 29/04/2015 09:04, Cecil Westerhof wrote:
Op Wednesday 29 Apr 2015 09:02 CEST schreef Ian Kelly:
On Wed, Apr 29, 2015 at 12:06 AM, Cecil Westerhof <ce...@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.
You might find this interesting
http://www.jeffknupp.com/blog/2013/02/06/write-cleaner-python-use-exceptions/
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