PHP - Create multidimensional array via a loop based on a count

Question

Having some trouble coming up with the right combination of count and foreach for a multidimensional array.

I'm currently doing the following to create an associative array from my db's returned result:

$sql = "SELECT g.id, g.shortname FROM games g ORDER BY g.id ASC";
        $query = $this->db->query($sql);

        if($query->num_rows() > 0):
            foreach($query->result() as $row):
                $data[$row->id] = $row->shortname;
            endforeach;
        return $data;
        else:
            return false;
        endif;

This of course produces the following array (which works fine; semi-faux code):

array ( [1] => CoolGame, [2] => AnotherGame, [3] => BetterGame, [4] => UglyGame)

....and so on

But what I want to do is automatically break up results (based on a count var/limiter) into groups via a multidimensional array like so:

array (Group 1 => 
         array([1] => CoolGame [2] => AnotherGame),
       Group 2 =>  
         array([3] => BetterGame [4] => UglyGame)
)

So in that example, my $depth_count = 2;

In case anyone is interested, I'm doing this to work with auto-generated <optgroup> tags for a multi select via CI's form helper's form_multiselect() function. Need some help with tweaking my PHP to allow for this. Thanks!

Answer 1

You can use php's array_chunk method. Notice its use in modified code below:

if($query->num_rows() > 0):
    foreach($query->result() as $row):
        $data[$row->id] = $row->shortname;
    endforeach;

    $data = array_chunk($data, 2);

return $data;

Answer 2

$nGroup = 1; $curGroup = '';
$nRow = 0;
foreach ($query->result() as $row){
  if ($nRow++ % 2 == 0){ // change 2 to your limiter
    $curGroup = 'Group ' . $nGroup++;
    $data[$curGroup] = array();
  }
  $data[$curGroup][$row->id] = $row->shortname;
}

Something like that? Keep track of the row you're on, the current group your adding to, and the group name. Then, every 2nd (or Nth) set, switch groups.