preg_replace_callback('/(.)(\1*)/',function($match){returnmb_strlen($match[0]).$match[1];},'abbcccdddd');
                            

functionprocessStr($str="abbcccdddd"){
$result='';
while(strlen($str)>0){
$tempStr=substr($str,0,1);
$result.=substr_count($str,$tempStr).$tempStr;
$str=str_replace($tempStr,'',$str);
}
return$result;
}