note 71371 added to function.isset

I am trying to decipher a peice of code and I am not sure what this is trying to do. I have seen the isset command used with the if statement but not sure what this does: $hi = !isset($_POST['HospID'])? NULL : $_POST['HospID']; ---- Server IP: 85.116.0.130 Probable Submitter: 86.145.217.104 ---- Manual Page -- http://www.php.net/manual/en/function.isset.php Edit -- https://master.php.net/note/edit/71371 Del: integrated -- https://master.php.net/note/delete/71371/integrated Del: useless -- https://master.php.net/note/delete/71371/useless Del: bad code -- https://master.php.net/note/delete/71371/bad+code Del: spam -- https://master.php.net/note/delete/71371/spam Del: non-english -- https://master.php.net/note/delete/71371/non-english Del: in docs -- https://master.php.net/note/delete/71371/in+docs Del: other reasons-- https://master.php.net/note/delete/71371 Reject -- https://master.php.net/note/reject/71371 Search -- https://master.php.net/manage/user-notes.php