number_format($str,'2','.',','); function number($k){    if(strpos($k,'.')===false){        $ok = $k.'.'.'00';    }else{    $arr = explode(".",$k);                     $a = substr($arr[1],0,2);    $number = empty($a) ? '00' :  $a;    $ok = $arr[0].'.'.$number;    }    return $ok;}echo  number_format(number(10000.456),2);