para

I'm trying to replace certain occurances of a substring within certain substrings of a string.
For example, if I have the string:
I would like to be able to use a preg_replace() call to change this to:
Where, in this example, <br>'s are removed, but only within <pre> blocks. Is this possible?

I'm not so great a PHP, and worse at regex; I came up with something like..
But it doesn't exactly work correctly. I'm sure this is far from what I want to

Might anyone be regex gurus?

Arevos

Maybe you should take advantage of preg_replace_callback:
[PHP]function remove_br_tags($matches) {
return preg_replace("/<br>/", "", $matches[0]);
}

$str = "blah1<br>blah2 blah3 <pre>asdf<br>123<br></pre> blah4 blah5<br>blah6";

$str = preg_replace_callback("/<pre>.*?<\/pre>/", "remove_br_tags", $str);[/PHP]

para

Thanks, worked great.