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I have a similar problem, over six hundred complex regexen to match against a busy logfile and related messages to issue depending on which regexps were matched. much the same problem as the OP

If I understand the regexp engine caching the compiled version of a regex if it is not going to change then I think this should be a reasonably efficient approach. Am I on the right tracks ? and is the /o unrequired as I have already interpolated the variable when the regex is first called ?

#!/usr/local/bin/perl -w use strict; my ($i, $compile_me, @names)=(1, "{my \@matches;", "no match"); while (<DATA>) { next if /^\s*$/; last if /END CONFIG/; chomp; my ($name, $reg)=split; push @names, $name; $compile_me.="push \@matches, $i if /$reg/o;"; $i++; } $compile_me.="\@matches}"; while (<DATA>) { chomp; print "\nmatches found for $_\n"; my @matches=eval $compile_me; foreach (@matches) { print $names[$_] , "\n" } } __DATA__ Fred_and_Friends fr.d Paul_and_co paul some_numbers \d{2} freud_likes_fred fr END CONFIG freud fred NaNa pauline 12312sdfsdf 2
Update with speed test

I have now run a comparative test over 300^H^H^H, sorry 416 lines of log, with my 672 pattern matches. First using the eval of a string containing all the regexen and returning match index numbers as above. Second is my old naive code holding an array with the regexen and doing a foreach through it against each line. I did not use the /o for the reasons given above it works fine without it

>time ./ real 0m1.49s user 0m0.68s sys 0m0.58s >time ./Monitor real 0m19.47s user 0m14.69s sys 0m0.50s >

I think the numbers speak for themselves


In reply to Re^2: Matching against list of patterns by Random_Walk
in thread Matching against list of patterns by Eyck

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