PHP - Mongo - $或

Question

I am using PHP/Mongo to query a data set like the following:

{
  description:
  {
    0:
      {level: (some int 0-50)},
    1:
      {level: (some int 0-50)},

  ...

    n:
      {level: (some int 0-50)}
   }
 }

How do I write the function, in php, that will build a dynamic query that searches for a level 40 and above, using $or and based on the number of description keys (0 ... n)?

What I currently have for a manual query is not working (I have a feeling it's because in some entries description.1, 2, 3 do not exist):

find("$or":{"description.0.level":[40,41,42,43,44,45,46,47,48,49,50],"descriptio‌​n.1.level":[40,41,42,43,44,45,46,47,48,49,50],"description.2.level":[40,41,42,43,‌​44,45,46,47,48,49,50],"description.3.level":[40,41,42,43,44,45,46,47,48,49,50]}})

It gives me an error:

Fatal error: Uncaught exception 'MongoCursorException' with message '$and/$or/$nor must be a nonempty array'

So, I need a function that will build the query dynamically, and work :).

Answer 1

For those interested, here is my final code for this problem (works).

$y = 0;
$descriptionLevels = 10; // set to 'n' levels as needed ...
while($y < $descriptionLevels){
    $filter['$or'][]['description.' . $y . '.level']['$in'] = range($startLevel, $endLevel);
    $y++;
}