- chr: documentation ( source)
- explode: documentation ( source)
- strtolower: documentation ( source)
<?php
$str = "16 18 9 22 1 3 25 12 19 20";
$chr = explode(" ", $str);
$out = "";
foreach($chr as $c) {
$out.= chr(65 + (int) $c);
}
print strtolower($out);