function CanCeL($text)
        {
            $dizi1=array("a","b");
            $dizi2=array("1","2");
            $text=str_replace($dizi1,$dizi2,$text);
            $text=preg_replace("@[^A-Za-z0-9\-_]+@i","",$text);
            $text=strtolower($text);
            return($text);
        } 

 
echo CanCeL("osman");