Find Constant Array key Names

getConstantArrayNames.php

<?php namespace yourName;
/**
 * return constant array key
 * @param  constant $const constant array name
 * @param  int $index index of constant array key value (in my case its int)
 * @return string        key name (string in my case)
 */
function getConstantArrayNames($const, $index) {
    $x = get_defined_constants(true);

    foreach ($x['user']['yourName\\'.$const] as $key => $value) {
        if ($value == $index)
        return $key;
    }
}
?>