num to alphanumeric

gistfile1.txt

    /**
     * Give  1 => A
     *          2 => B
     *          etc
     **/
    public function num2alpha($number) {
        $number--;
        $result = '';
        for ($i = 1; $number >= 0 && $i < 10; $i++) {
            $result = chr(0x41 + ($number % pow(26, $i) / pow(26, $i - 1))) . $result;
            $number -= pow(26, $i);
        }

        return $result;
    }