Re^4: Making regex /g match continuously

Thanks. I think I like the second approach best.

If I can, a bit of an elaboration though; of the 3 approaches you suggested, which is most efficient when there is not a match? I notice that when my complicated regex's do not match that I max the CPU on my server and the HTTP aspect has to time out. If the regex matches, it takes mere fractions of a second.

Is there a way within these approaches that I can minimize the wasted effort of the regex in a case that not all 'int's will match?

Thanks again.

Comment on Re^4: Making regex /g match continuously

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Re^5: Making regex /g match continuously by Roy Johnson (Monsignor) on Jan 07, 2005 at 20:39 UTC
I expect that option 1 would be the most efficient. Option 2 as originally described doesn't work (but see Tye's response below), because when a match fails, pos gets reset, so it won't be at the end of the string. Instead, you have to set a flag by testing pos against length within the loop: `while (<DATA>) { my @accum; my $ate_the_whole_thing = 0; while (/\G$item_regex/g) { push @accum, [$1, $2, $3]; $ate_the_whole_thing = (pos() == length); } if ($ate_the_whole_thing) { print join ',', @$_, "\n" for @accum; } }` [download] Option #3 would put a lookahead in the iterative match, which is expensive (as I noted), but does work: `while (<DATA>) { my @accum; push @accum, [$1, $2, $3] while (/\G$item_regex(?=$item_regex\Z)/g) +; print join ',', @$_, "\n" for @accum; }` [download] Caution:* Contents may have been coded under pressure.	[reply] [d/l] [select]
Re^6: Making regex /g match continuously (/c) by tye (Sage) on Jan 08, 2005 at 07:59 UTC
Option 2 is the clear choice for me. I guess you missed the /c option in perlop. - tye	[reply]
Re^7: Making regex /g match continuously (/c) by Roy Johnson (Monsignor) on Jan 10, 2005 at 18:37 UTC
One of those little-used operators I'd never noticed before. Thanks! Caution: Contents may have been coded under pressure.	[reply]
Re^6: Making regex /g match continuously by scottb (Scribe) on Jan 07, 2005 at 22:02 UTC
Looks good, thanks. For the record, I went with option 1.	[reply]
Re^5: Making regex /g match continuously by Eimi Metamorphoumai (Deacon) on Jan 07, 2005 at 20:37 UTC
Well, you can check whether `pos` matches `length`.	[reply]