两个json二维数组怎么，进行拼接？

$banner_m=M('banner');
    $where_ban['b_id']=1;
    $banner_m=$banner_m->where($where_ban)->field('img')->select();
    $pars_json = json_encode($banner_m);


    $lan_m=M('Lanmu');
    $where_lan['parentid']=3;
    $lan_m=$lan_m->where($where_lan)->field('fname,typeimg,content')->select();
    $par_json = json_encode($lan_m);

现弄成数组
$all=array('banner_m'=>$banner_m,'lan_m'=>$lan_m);
在转json就可以了
json_encode($all)