How to read $priority_level = (!isset($priority) || empty($priority))?3:$priority;

[shelbytll]

Hi,
can anyone teach me how to read such codes:

$priority_level = (!isset($priority) || empty($priority))?3:$priority;

I don't understand the above codes at all.

Thanks

[tserbis]

if ( ! isset ($priority) || empty($priority) ) {
$priority_level = 3;
}
else {
$priority_level = $priority;
}