How would I go about optimizing this:

http://www.ubbdev.com/db/uploads/pagination_621.txt

If you have time can you tell me the principals behind making the changes?

I'm not sure what can be done to speed it up... the best thing to do is just tinker with it as much as you can, trying different ideas, etc...

Check out the Benchmark module:

http://www.perldoc.com/perl5.6.1/lib/Benchmark.html

CC - out of curiousity, if you know O() notation, have you ever found it usefull with perl?

It's hard to read due to the inconsistent indentation, but it looks like a lot of common expressions could be moved outside of the loops.

Also, according to Programming Perl (3rd Ed., chap 24), using join is more efficient than a series of string concatenations.

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by jordo:
CC - out of curiousity, if you know O() notation, have you ever found it usefull with perl?</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">O notation is essentially a way of representing execution times/speeds for an algorithm. An algorithm can be represented in any languague [in some more effectivly than others], thus it's completely independant of relating it to perl, C, Java, etc. In other words, it's always useful when you're dealing with algorithms

--mark

yeah i know i was just curious whether they use it when developing ubb or whether the use Benchmark modules more heavily.

We don't use it unless we're not getting acceptable performance...

Split the variables earlier?