How would you translate this in PHP ?

[litewarez]

$result = (isset($var[0]) ? $var[0] : null); 

by the way you explained it you might want

for($i=0;$<=count($var);$i++)
{
    switch($i)
    {
        case 0:
            //First item here
            $var[$i] = strtolower($var[$i]);
        break;
        default:
            //All other elements in the array
            $var[$i] = strtoupper($var[$i])
        break;
    }
}