01.$numstring = '12 21 22 22 23 32 33 33';
02.
03.if (!is_string($numstring)) {
04. throw new \Exception('$numstring must be string!');
05.}
06.
07.$numArray = explode(' ', $numstring);
08.$numArray = array_unique($numArray);
09.$numstring = implode(' ', $numArray);
10.
11.echo $numstring;
