- var_dump: documentation ( source)
- array_keys: documentation ( source)
- ksort: documentation ( source)
- join: documentation ( source)
<?php
$some_array = array (
0 => 1,
'x' => 1,
2 => 1,
'a' => 1,
1 => 1,
'z' => 1);
ksort($some_array);
var_dump($some_array);
echo(join("", array_keys($some_array)));