Getting started with python

[James Stroud]

Steve Holden wrote:
> James Stroud wrote:
>> Steve Holden wrote:
>>> You'd be worth more if you'd used elif and omitted the continue 
>>> statements, but for a first solution it's acceptable.
>>
>> Depends on what you are after.
>>
>> py> s = """
>> ... for i in xrange(1,101):
>> ...   if not i % 15:
>> ...     continue
>> ...   if not i % 5:
>> ...     continue
>> ...   if not i % 3:
>> ...     continue
>> ...   else:
>> ...     pass
>> ... """
>> py> t = timeit.Timer(stmt=s)
>> py> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
>> 40.49 usec/pass
>> py> s = """
>> ... for i in xrange(1,101):
>> ...   if not i % 15:
>> ...     pass
>> ...   elif not i % 5:
>> ...     pass
>> ...   elif not i % 3:
>> ...     pass
>> ...   else:
>> ...     pass
>> ... """
>> py> t = timeit.Timer(stmt=s)
>> py> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
>> 40.88 usec/pass
>>
> 
> To be strictly comparable you should have pass statements before the 
> continue statements as well.  Ignoring that, clearly it's well worth 
> saving that extra 390 nanoseconds each time round the loop.
> 
> Repeat after me "premature optimization is the root of all evil".
> 
>   http://en.wikipedia.org/wiki/Optimization_(computer_science)
> 
> regards
>  Steve

The point is that both work equally as well unless (1) you are biased by 
a particular style or (2) you split little bitty hairs to even finer hairs.