python coding contest

[Claudio Grondi]

Steven D'Aprano wrote:
> On Sun, 01 Jan 2006 15:49:58 +0100, Claudio Grondi wrote:
> 
> 
> 
>>What I have thought about as a simpler/better solution is a method 
>>allowing to avoid processing the content of the string or long integer 
>>object by looping over its content. 
> 
> 
> How can you avoid looping over its content? Whether you do it yourself
> using "for byte in array" or similar, or Python does it for you
> (using array.tostring perhaps), *something* has to walk through the bytes.
> 
> If you don't like walking the string, write a function to do it once, and
> then use the function.
> 
> 
>>I suppose, that knowing enough about 
>>Python internals it must be possible to change only the object type not 
>>beeing forced to process the content i.e. the value itself, what in case 
>>of big size of data to convert with methods like this above wastes CPU 
>>time.
> 
> 
> I'm reminded of a time I was going for a drive in the country when I drove
> past an apple orchid. Standing in the orchid was a farmer with a pig. He
> lifted the pig into the air, and the pig then bit an apple and slowly
> chewed it. The farmer then carried him over to another branch, and the pig
> ate another apple.
> 
> I was so surprised I stopped my car and wandered over to ask the farmer
> what he was doing.
> 
> "I'm feeding apples to my pig," he replied.
> 
> "Wouldn't it save time to just pick some apples and feed them to the pig?"
> 
> The farmer looked at me like I was an idiot. "What's time to a pig?"
> 
> 
> The moral of the story is, before spending time working on some scheme to
> save CPU time, you better be absolutely sure that firstly, you are going
> to save CPU time, secondly, that it is enough CPU time to be worth saving,
> and thirdly, that you aren't wasting more of your own time to do it.
> 
> 
> 
It's a funny story :-))

, but in my eyes not appropriate in given context, because my prior goal 
is to understand some more about Python internals, i.e. what is and if 
it is at all a differerence between the internal representation of a 
string and a long integer.

I know, I should probably look into the C source of Python, but I 
suppose it could be too hard for me to find the appropriate piece of 
code, so I welcome any hints.

If I knew the internal representation of string and long integer objects 
and were able to read/write to memory and point an identifier at a given 
memory address, a conversion between long integer and string types were 
probably nothing else as changing some bytes and repointing an 
identifier (assuming that string and long integer values are in memory 
the same data if they represent the same value). That it would save CPU 
time is secondary here, but with increasing costs of energy making the 
number on my electrical power bill higher each year due to higher power 
consumption with increasing number of programs I run (it makes a 
difference of 50 Watt between an algorithm keeping the CPU 100% busy and 
an algorithm using only 1% of it) it is not necessarily paranoia driving 
one to consider potential savings of CPU time.
In this context the example of the bigdec class comes to my mind, where 
usage of another algorithm made it possible to cut down power 
consumption and time of printing a decimal form of the largest known 
prime number from 7 hours of a 100% busy CPU down to 7 seconds!

Claudio