On Jul 15, 3:00 pm, Steve Holden <[EMAIL PROTECTED]> wrote: > Alex Popescu wrote: > > On Jul 14, 5:55 am, "Gabriel Genellina" <[EMAIL PROTECTED]> > > wrote: > >> So, as always, one should measure in each specific case if optimization is > >> > >> worth the pain [...]. > > > I hope I am somehow misreading the above sentence :-). IMO synonim > > language contructs > > should result in the same performance or at least have clear/ > > documented performance. > > That's a fine opinion, how would you enforce it? Should we go throught > he interpreter slowing down the faster to each pair of alternative > constructs? ;-) It's inevitable there'll be differences in execution > time between equivalent constructs, and in that case you have to test to > find the better in your specific situation. > > The real issue here is that in 95% or more of the source of most > programs speed/performance isn't that much of an issue anyway. > > > I don't think we really want to see in code something like: > > > if threshold: > > do_it_with_list_function > > else: > > do_it_with_list_comprehension > > This would most certainly be a premature optimization which, as has been > repeated many times on this list, is the root of much evil in > programming. As Gabriel mentioned, you only need to do it if it's "worth > the pain", which in most case it won't be. It isn't worth spending even > five minutes to shave a minute off the performance of a ten-minute > program that is only run once a week, for example. > > Ultimately we have to be pragmatic: circumstances alter cases, and it's > usually not worth spending the time to improve execution speed except > for the most critical parts (the innermost nested loops) of production > programs. > > regards > Steve > -- > Steve Holden +1 571 484 6266 +1 800 494 3119 > Holden Web LLC/Ltd http://www.holdenweb.com > Skype: holdenweb http://del.icio.us/steve.holden > --------------- Asciimercial ------------------ > Get on the web: Blog, lens and tag the Internet > Many services currently offer free registration > ----------- Thank You for Reading -------------
Steve, I fully agree with you (I am a newbie only to Python and not to programming ;-)). My point was that this thread may be misleading to newbies, because it is discussing corner cases performance of the 2 equivalent language constructs, while it should most probably be about the fact that the 2 solutions are equivalent and the only difference is probably readability (or maybe something like: list function is prefered when there are no additional constraints on the list comprehension construct). bests, ./alex -- .w( the_mindstorm )p. -- http://mail.python.org/mailman/listinfo/python-list