implode 多维数组转一维数组并字符串输出

    //多维数组返回一维数组，拼接字符串输出
    public function r_implode( $glue, $pieces )
    {
       foreach( $pieces as $r_pieces )
       {
         if( is_array( $r_pieces ) ) {
           $retVal[] = self::r_implode( $glue, $r_pieces );
         } else {
           $retVal[] = $r_pieces;
         }
       }
       return implode( $glue, $retVal );
     }