Regex problems...

Getting my head around regular expressions

[mnet1]

I have been reading up on regex etc but despite what I try I can't seem to get my PHP preg_replace's to work the way I want.

Basically all I'm looking to do is replace all linked URLs in a string with links to a PHP file as follows

<a href="hello.html?db=blahblah">Hi</a><a target="_blank" href="goodbye.html">goodbye.html</a>

... becomes ...

<a href="index.php?file=hello.html&db=blahblah">Hi</a><a target="_blank" href="index.php?file=goodbye.html">goodbye.html</a>

You'll note two unique things about this - a) I need it to be able to handle pre-existing query strings as per the hello.html example and b) I only want linked URLs to be replace, not every URL (as per goodbye.html).

Any thoughts / code would be very much appreciated - I've been beating my head against this wall for a few days now :(

[DrDoc]

Welcome to Webmaster World!

How about this:

$newstring = preg_replace("/href=\"/","href=\"index.php?file=",preg_replace("/\?/","&",$oldstring));

edited typos

[DrDoc]

Maybe I should explain what the code does, too:

preg_replace("/\?/","&",$oldstring)

replaces any?'s with "&" (I'm using the HTML entity & here).

The other preg_replace replaces href=" with href="index.php?file=

Hence,

href="hello.html?db=blahblah"

would be

href="hello.html[b]&[/b]db=blahblah"

after the first preg_replace, and then

href="[b]index.php?file=[/b]hello.html&db=blahblah"

after the second.

href="goodbye.html"

remains unchanged in the first preg_replace, but becomes

href="[b]index.php?file=[/b]goodbye.html"

after the second.

[mnet1]

Thanks so much for that! Other than a missing ')' it worked straight out of the box :)

Thanks also for the welcome, this seems like a great community.