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Re: can't find the right PCRE pattern for a preg_match_all

Posted by greatprovider on 06/06/06 17:05

thank you for the explanation..."it all makes sense now..." until i
find another expression....heh

thank you again,
GP

Rik wrote:
> greatprovider wrote:
> > hah...that was the trick...thank you all...
> >
> > one last question...now would anyone mind explaining me how "$1"
> > works?
>
> In a regular expression, you can "capture" pieces that match a pattern with
> (). The number after the $ indicates which piece, captures are numbered from
> the first opening '('.
>
> For instance:
> **567HJK
>
> '/((\*{2})(\d+))/'
>
> $1 will contain the match: '**567';
> $2 will contain the match: '**';
> $3 will contain the match: '567';
>
> Normally, pieces that have to match a certain regex, but aren't used any
> further, don't need (). In some cases, it's necessary for the pattern. In
> that case, you could just use the numbered matches you need, discarding the
> others (with multiple captures in a regex, it is absolutely not necessary to
> use them all). To keep a complex regex more clear, you could also make a
> 'non-capturing' group by adding ?: after the opening. For instance:
> (?:\s+(\d+)) will capture the digits in $1, instead of $2, because the first
> parenthesis is told not to capture anything.
>
> Want to learn more about regexes?
> http://www.regular-expressions.info/tutorialcnt.html was a big help for me.
>
> Grtz,
> --
> Rik Wasmus

 

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