PHP: why is this null different from the other null

Question

hi i tried 2 things what should be the same however it my testing says different does anyone know why the only thing i do is put it in a variable...

    if ($_SESSION[$something] === null)
        echo("this is null");

$_SESSION[$something] does not exists so it indeed says: "this is null". now look at this

$theSession = $_SESSION[$something];

if ($theSession === null)
    echo("this is null");

now it does not say "this is null" while it should be exactly the same right?

Answer 1

You need a $ in front of theSession in the second block of code.

You do may not need the $ in front of something. You only need it if $something is holding a string of the session variable name. Otherwise if something is the session variable name you dont need the $.

Answer 2

You should also consider using is_null to check is a variable contains a null value.