php regular expression to match domain name in URL

$search = '~^(([^:/?#]+):)?(//([^/?#]*))?( [^?#]*)(?([^#]*))?(#(.*))?~i';
$url = 'http://www.php.net/pub/ietf/uri /#Related';
$url = trim($url);
preg_match_all($search, $url ,$rr);
printf("The output URL data is:  %sn",var_export( $rr ,TRUE));
/*
Each group is as follows
 $1 = http:
 $2 = http
 $3 = //www. php.net
 $4 = www.php.net
 $5 = /pub/ietf/uri/
 $6 =
 $7 =
 $8 = #Related
 $9 = Related
*/
?> ;

Another concise code is provided here:

// Get the hostname from the URL
preg_match("/^(http ://)?([^/]+)/i", "http://www.php.net/index.html", $matches);
$host = $matches[2];
// from Get the last two segments from the host name
preg_match("/[^./]+.[^./]+$/", $host, $matches);
echo "domain name is: {$matches[0]} n";
?>

Output after execution: domain name is: php.net