Need help in understanding a python code

[Steven D'Aprano]

On Sun, 16 Nov 2008 04:34:40 -0800, John Machin wrote:

> Nothing to do with style. It was the screaming inefficiency of:
>    if non_trivial_condition: return x
>    if not non_trivial_condition: return y
> that fired me up.

"Screaming inefficiency"?

Try "micro-optimization". The difference in execution time between "if 
x... if not x..." versus "if x... else..." on my slow, underpowered 
machine is about 10**-8 seconds. If that's your idea of "screaming 
inefficiency" I can't understand why you're programming in Python in the 
first place.

Of course, if x is an expensive function call (say, a network lookup or 
database query rather than a relatively cheap list indexing operation) 
then the more readable, Pythonic solution will also be significantly 
faster. There's no doubt that it should be preferred -- I'm not defending 
it, as such, just pointing out the over-reaction of dismissing what is a 
generally well-written and thought-out article on the basis of a 
triviality.


 
>> http://en.wikipedia.org/wiki/Style_over_substance_fallacy
> 
> Quoted Wikipedia -> instant disqualification -> you lose. Good night.


Oh gosh, well, you've certainly proven your case, how could I be so 
stupid? My apology for thinking that you were acting like an arrogant, 
bad-tempered dick. I don't know *what* I was thinking.



-- 
Steven
who would link to Wikipedia for the definition of sarcasm except I've 
already lost once in this thread and that's enough.