PHP strrchr parse int

I've got a problem. This is my PHP code :

$extract = $query;
$extractpoint = strrchr($extract, ".");

So, $extract is a parse_url of my website address. Exemple : http://test.com?param.6

$extract = param.6 and $extractpoint = .6

BUT, I want a solution to have only the 6, without the point.

Can you help me with that ?