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Re^2: fastest pattern match

by flounder99 (Friar)
on Jun 24, 2002 at 19:50 UTC ( #176918=note: print w/ replies, xml ) Need Help??


in reply to Re: fastest pattern match
in thread fastest pattern match

You should use m/$regex/o or the regex will be compiled every iteration, slowing things down considerably

--

flounder


Comment on Re^2: fastest pattern match
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Re: Re^2: fastest pattern match
by d4vis (Chaplain) on Jun 24, 2002 at 20:11 UTC
    Good advice in general,
    but in this case there'll only be one interation.

    Update: Fastolfe's right...my bad...mea culpa

    ~monk d4vis
    #!/usr/bin/fnord

      Why? If we were sure the match would always occur on the first line, why search for it at all?
Re: Re^2: fastest pattern match
by japhy (Canon) on Jun 24, 2002 at 22:29 UTC
    Incorrect. It will not be compiled on every iteration, but its string form will be compared with its previous string form, to see whether it needs recompiling.

    _____________________________________________________
    Jeff[japhy]Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area)
    s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

      Thanks,

      I remember reading that it still did the recompile even if the variable in the regex did not change. Of course I read that a LONG time ago. Apparently it has been fixed.(probably a long time ago) So would the /o faster by avoiding the extra string compare? I know this would probably be insignificant unless there where a bajillion iterations. But I was just curious.
      Do you even know anything about regexes? (see sig)

      --

      flounder

      Do you even know anything about perl?
      --Anonymous Coward to Tom Christiansen on slashdot

Re: JANRQ :O(
by frankus (Priest) on Jun 25, 2002 at 12:40 UTC

    That's JAN-AR-IK..(like generic) Just another Regexp Question.

    Also it might be worth mentioning that meta characters in $regex will still be parsed. Make sure you intended that to happen.

    --

    Brother Frankus.

    ¤

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