While Statement

[Dave Angel]

Tim Wintle wrote:
> On Fri, 2009-05-22 at 13:19 +0200, Andre Engels wrote:
>   
>> number/total = 998/999 = 0
>> number/total*100 = 0*100 = 0
>> float(number/total*100) = float(0) = 0.0
>>
>> Change "float(number/total*100)" to "float(number)/total*100" and it
>> should work:
>>     
>
> I'd use:
>
>  (number * 100.)/total
>
> - works because
>  <int> * <float> => <float> 
>
> It's a minor thing, but it's much faster to cast implicitly as you miss
> the python function call overhead - it's no extra work to write, and for
> numerical things it can really speed things up.
>
>   
>>>> a = timeit.Timer("float(200)/5*100")
>>>> b = timeit.Timer("(200*100.)/5")
>>>> a.timeit(10000000)
>>>>         
> 12.282480955123901
>   
>>>> b.timeit(10000000)
>>>>         
> 3.6434230804443359
>
> Tim W
>
>
>
>   
It's the old-timer in me, but I'd avoid the float entirely.  You start 
with ints, and you want to end with ints.  So simply do the multiply 
first, then the divide.

 number * 100/total

will get the same answer.