[PLUG] OT: Formula For Determining # Of Digits In An Integer

[Eric Wilhelm]

# The following was supposedly scribed by
# Jason Van Cleve
# on Thursday 17 February 2005 04:31 pm:

>> y = 1;
>> while (x /= 10)
>>   y++;
>
>This is basically what I have now.  It's just that the method I'm
>writing is already called in a loop, so I wanted a single-operation
>formula instead of a loop algorithm.

Long version of Galens reply:
You might want to benchmark the loop vs the log() method.  I'm not sure 
exactly how java does it or whether it's somehow native in the 
processor, but IIRC from mathematics, logarithms are only computable as 
an infinite series.  So, barring some magic happening in the processor 
that I don't know about, a hand-written log() function (which iterates 
until the desired accuracy is reached (and remember, you're going to 
call this twice)) is going to be slower than your simple reductive 
loop.

Ok, so none of the details are too sharp here.  Point is:  benchmark.  
Don't assume that mathematical elegance is always faster than brute 
force.

Anyway, I'd probably just do length(sprintf("%0.0f", $num)) in perl 
(assuming a positive number.)

--Eric
-- 
Cult: A small, unpopular religion.
Religion: A large, popular cult.
                                                  -- Unknown
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