static public function extract($data, $keys=null)
    {
        if ($data) {
            if ($keys) {
                $list = [];
                $keys = static::explode('\,\|', $keys);
                foreach ($keys as $k) {
                    $list[] = isset($data[$k]) ? $data[$k] : null;
                }
                return $list;
            }
        }
        return $data;
    }
static public function extract($data, $keys=null)
    {
        if ($data) {
            if ($keys) {
                $list = [];
                $keys = static::explode('\,\|', $keys);
                foreach ($keys as $k) {
                    $list[] = isset($data[$k]) ? $data[$k] : null;
                }
                return $list;
            }
        }
        return $data;
    }
static public function extract ( $ data , $ keys = null ) { if ( $ data ) { if ( $ keys ) { $ list = [ ] ; $ keys = static :: explode ( '\,\|' , $ keys ) ; foreach ( $ keys as $ k ) { $ list [ ] = isset ( $ data [ $ k ] ) ? $ data [ $ k ] : null ; } return $ list ; } } return $ data ; }
extract array by keys
@param  array $data
@param  mixed $keys array or string
@return array
extract array by keys