better way to replace query string value in a given url

Question

Okay.. so basically, say we have a link:

$url = \"http://www.site.com/index.php?sub=Mawson&state=QLD&cat=4&page=2&sort=z\";

Answer 1

Well, I had same problem, found this question, and, in the end, prefered my own method. Maybe it has flaws, then please tell me what are they. My solution is:

$query=$_GET;
$query['YOUR_NAME']=$YOUR_VAL;
$url=$_SERVER['PHP_SELF']. '?' .  http_build_query($query);

Hope it helps.