On Apr 2, 6:57 pm, Steven D'Aprano <st...@remove-this- cybersource.com.au> wrote: > On Fri, 02 Apr 2010 12:39:16 -0700, Patrick Maupin wrote: > > On Apr 2, 2:38 pm, Ethan Furman <et...@stoneleaf.us> wrote: > [...] > >> Sounds like a personal preference issue, rather than a necessary / > >> unnecessary issue -- after all, if you call that function a thousand > >> times, only once is mongo not defined... clearly the exception. ;) > > >> ~Ethan~ > > > Well, I think the whole discussion has basically been about personal > > preference. OTOH, but if you call the function a few million times, you > > might find the cost of try/except to be something that you would rather > > not incur -- it might become a performance issue rather than a personal > > choice issue. > > The cost of a try...except is *very* low -- about the same as a pass > statement:
Agreed. In the example above, if frobnicate() is a null function, the try/except adds about 5% to execution time on my machine. If I were really worried about execution time, I would use a closure *for this particular example* as I mentioned elsewhere. However, the cost of the try/except is not zero, and when I have something I prefer looking at (the __getattr__ doesn't clutter up the main-line execution with conditionals for stuff that only gets used once at initialization) that is always known to be cheaper in execution, that's what I use. I suppose some people might not like looking at the __getattr__, but this is a memoization technique I use quite often, so I find it idiomatic. Regards, Pat -- http://mail.python.org/mailman/listinfo/python-list
