function set($str) {
$array = str_split($str);
$st = array_combine($array, $array);
return $st;
}
$str = "PHP Programming";
print_r(set($str));
/*
run:
Array
(
[P] => P
[H] => H
[ ] =>
[r] => r
[o] => o
[g] => g
[a] => a
[m] => m
[i] => i
[n] => n
)
*/