How would you rewrite this snippet without using eval?

Hi all, I'm rewriting a script trying to avoid using functions that might pose a security threat if used incorrectly. I have a portion of code that looks like the one pasted below. I don't seem to be able to avoid using eval without introducing too many changes, losing in simplicity. Here's the code: <?php echo Logic::getFirstValue(); // Output: first value class Logic { public static function getFirstValue() { return Data::getData('$firstArray','firstKey'); } } class Data { private static $firstArray = array ('firstKey'=>'first value'); private static $secondArray = array ('secondKey'=>'second value'); public static function getData($array, $key) { $string = 'return self::'.$array.'[\''.$key.'\'];'; return eval ($string); } } ?> How would you rewrite the snippet without using eval and still keeping things very straightforward? Thanks for your attention!