regex mystery

[Red]

In netscape bookmark files, there are lots of lines like this:
<DT><A HREF="http://www.commondream s.org/" ADD_DATE="10915 00674"
LAST_CHARSET="I SO-8859-1" ID="rdf:#$uiYyb 3">Common Dreams</A>

I want to eliminate the excess attributes and values to get this:
<DT><A HREF="http://www.commondream s.org/">Common Dreams</A>

I almost succeed with this:
$lines[]=preg_replace(" {(<A HREF=\".*\")( ADD.*)(>.*</A>)}","\\1\\3" ,
$line);

The only problem is the explicit "ADD". The code only works is there is
an ADD_DATE attribute immediately after the url. I tried replacing (
ADD.*) with ( .*), which I thought would match everything up to the ">":
$lines[]=preg_replace(" {(<A HREF=\".*\")( .*)(>.*</A>)}","\\1\\3" , $line);

For some reason, this does not find a match. Since " ADD" is the same as
..*, I don't understand why I need the explicit " ADD".

How do I match without the explicit " ADD"

[steve]

Re: regex mystery

"Red" wrote:[color=blue]
> In netscape bookmark files, there are lots of lines like this:
> <DT><A HREF="http://www.commondream s.org/"
> ADD_DATE="10915 00674"
> LAST_CHARSET="I SO-8859-1" ID="rdf:#$uiYyb 3">Common Dreams</A>
>
> I want to eliminate the excess attributes and values to get this:
> <DT><A HREF="http://www.commondream s.org/">Common
> Dreams</A>
>
> I almost succeed with this:
> $lines[]=preg_replace(" {(<A HREF=\".*\")(
> ADD.*)(>.*</A>)}","\1\3",
> $line);
>
> The only problem is the explicit "ADD". The code only works is[/color]
there[color=blue]
> is
> an ADD_DATE attribute immediately after the url. I tried replacing[/color]
([color=blue]
>
> ADD.*) with ( .*), which I thought would match everything up to the
> ">":
> $lines[]=preg_replace(" {(<A HREF=\".*\")(
> .*)(>.*</A>)}","\1\3", $line);
>
> For some reason, this does not find a match. Since " ADD" is the[/color]
same[color=blue]
> as
> ..*, I don’t understand why I need the explicit " ADD".
>
> How do I match without the explicit " ADD"[/color]

I could not follow the code, but this should work
ADD_DATE="10915 00674"

$changedlined = preg_replace("/ADD_DATE\=\"\d+ \"/", ’’,
$originalline);

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[Michael Fesser]

Re: regex mystery

.oO(Red)
[color=blue]
>In netscape bookmark files, there are lots of lines like this:
><DT><A HREF="http://www.commondream s.org/" ADD_DATE="10915 00674"
>LAST_CHARSET=" ISO-8859-1" ID="rdf:#$uiYyb 3">Common Dreams</A>
>
>I want to eliminate the excess attributes and values to get this:
><DT><A HREF="http://www.commondream s.org/">Common Dreams</A>
>
>I almost succeed with this:
>$lines[]=preg_replace(" {(<A HREF=\".*\")( ADD.*)(>.*</A>)}","\\1\\3" ,
>$line);
>
>The only problem is the explicit "ADD". The code only works is there is
>an ADD_DATE attribute immediately after the url. I tried replacing (
>ADD.*) with ( .*), which I thought would match everything up to the ">":
>$lines[]=preg_replace(" {(<A HREF=\".*\")( .*)(>.*</A>)}","\\1\\3" , $line);
>
>For some reason, this does not find a match. Since " ADD" is the same as
>.*, I don't understand why I need the explicit " ADD".[/color]

It's because of the default greediness of the quantifiers. The .* after
the HREF=\" in your second pattern is quite hungry and eats up every-
thing until the last " in the tag, including the ADD_DATE and everything
else. You can change this behaviour with the U-modifier, e.g.

$pattern = '#(<a href=".*").*(>. *</a>)#iU';
$replace = '$1$2';
$lines[] = preg_replace($p attern, $replace, $line);

Pattern Modifiers
<http://www.php.net/manual/en/pcre.pattern.mo difiers.php>

HTH
Micha

[Red]

Re: regex mystery

Michael Fesser wrote:[color=blue]
> .oO(Red)
>
>[color=green]
>>In netscape bookmark files, there are lots of lines like this:
>><DT><A HREF="http://www.commondream s.org/" ADD_DATE="10915 00674"
>>LAST_CHARSET= "ISO-8859-1" ID="rdf:#$uiYyb 3">Common Dreams</A>
>>
>>I want to eliminate the excess attributes and values to get this:
>><DT><A HREF="http://www.commondream s.org/">Common Dreams</A>
>>
>>I almost succeed with this:
>>$lines[]=preg_replace(" {(<A HREF=\".*\")( ADD.*)(>.*</A>)}","\\1\\3" ,
>>$line);
>>
>>The only problem is the explicit "ADD". The code only works is there is
>>an ADD_DATE attribute immediately after the url. I tried replacing (
>>ADD.*) with ( .*), which I thought would match everything up to the ">":
>>$lines[]=preg_replace(" {(<A HREF=\".*\")( .*)(>.*</A>)}","\\1\\3" , $line);
>>
>>For some reason, this does not find a match. Since " ADD" is the same as
>>.*, I don't understand why I need the explicit " ADD".[/color]
>
>
> It's because of the default greediness of the quantifiers. The .* after
> the HREF=\" in your second pattern is quite hungry and eats up every-
> thing until the last " in the tag, including the ADD_DATE and everything
> else. You can change this behaviour with the U-modifier, e.g.
>
> $pattern = '#(<a href=".*").*(>. *</a>)#iU';
> $replace = '$1$2';
> $lines[] = preg_replace($p attern, $replace, $line);
>
> Pattern Modifiers
> <http://www.php.net/manual/en/pcre.pattern.mo difiers.php>
>
> HTH
> Micha[/color]


What a handy modifier, thanks.

red