in reply to Re: A complex recursive regex,help
in thread A complex recursive regex,help

Hi BrowserUk,

My request was not clear, I think , Actually I need all the |xx| changed to |x x| and hence now I have used the tachyon answer of backward and forward assertion which I did not know much on before and I have seen your node once that uses < > code and then assigning $1 to a local variable inside the regex itself which was a lovely piece of regex , but I sure have to read and practice it thoroguhly BrowserUk, about backward, forward asssertions,and few other concepts of regex,THANKS A BUNCH



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Re: Re: Re: A complex recursive regex,help
by BrowserUk (Patriarch) on Feb 06, 2003 at 01:44 UTC

    Sorry. I misunderstood your requirement (though it could have been stated a little more clearly:^).

    This one (I think does what you want, edge case as well and is relatively simple. 

    $s = "xx|xx|xxxx|xx|xxx|xx|xx|xx";
$s =~ s[(?<!x)(x)(x)(?!x)][$1 $2]g;
print $s;
x x|x x|xxxx|x x|xxx|x x|x x|x x

    [download]

    Update Thinking about it, stick with tachyon's as this will fall over if your data contains any occurance of xx without |'s or x's on either side.

    Examine what is said, not who speaks.

    The 7th Rule of perl club is -- pearl clubs are easily damaged. Use a diamond club instead.

[reply]
[d/l]
      Hi ,

      The cases where the xx appears last are clearly taken care of by your regex BrowserUk,the part I am not understanding is that you are saying that it will fall over if yout date containes any occurances of xx without |'s or x's on either side, please give an instance of this BrowserUk, in terms of data to facilitate the understanding as yoru regex is doing pretty good in all data strings

[reply]

        An example where mine falls over, but I think tachyon's wouldn't. 

        $t = "xyxxy|xx|xy|xx|yy|yxxy xx x"
$t =~ s[(?<!x)(x)(x)(?!x)][$1 $2]g;

print $t
xyx xy|x x|xy|x x|yy|yx xy x x x

        [download]

        Examine what is said, not who speaks.

        The 7th Rule of perl club is -- pearl clubs are easily damaged. Use a diamond club instead.

[reply]
[d/l]

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