Online PHP editor | refs for Q8iqQ

<?php $cosas = array( 'true' => TRUE, 'false' => FALSE, 'null' => NULL, 'empty' => "", 'positive' => 1, 'negative' => -1, 'zero' => 0 ); $cosas = array_filter($cosas, function($k){ return TRUE; }); foreach($cosas as $nombre => $cosa) { echo "* $nombre\n"; echo "\tisset:\t" . ( isset($cosa) ? "TRUE" : "FALSE" ) . "\n"; echo "\ti_null:\t" . ( is_null($cosa) ? "TRUE" : "FALSE" ) . "\n"; echo "\tempty:\t" . ( empty($cosa) ? "TRUE" : "FALSE" ) . "\n"; echo "\teval:\t" . ( $cosa ? "TRUE" : "FALSE" ) . "\n\n"; }