Your problem is that you're iterating through the file over and over and over. You go through each line in the file N times, where N is the number of ranges. And you do that 72 times. So, your runtime is 72 * Ranges * lines_in_file. Oops!

Plus, the line @file = <FILE>; puts the entire file into RAM. A 22MB file translates to, probably, 100MB - 200MB in RAM. Add the overhead of Perl and anything else you're doing and you could be using 300MB+ of RAM. If you're doing this on a smaller machine, you could be swapping memory like crazy, which will kill your program's runtime. (And, it might even kill the machine.)

A much better idea would be to pre-process the file, maybe by loading it into a database. Then, do your work against that. Another idea would be to sort the file. That way, you can short-circuit your processing.

The important thing is that you have a program that works. Optimizing for speed once you have accuracy down is good. Optimizing for accuracy once you have speed down is ... harder.

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Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
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In reply to Re: inefficient code? works on small files ok but not larger ones by dragonchild
in thread inefficient code? works on small files ok but not larger ones by Anonymous Monk

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