How to create an multidimensional array in VB.NET or PHP

Question

I have a data set that is setup for comments. I have levels and a sort column but now I would like to either get this in an array or display it somehow in a meaningful way:

id    comment         Parentid Level sortcol
2    Test                NULL    0 0x00000002
4    This is the Second    NULL    0 0x00000004
5    First Reply          4    1 0x000000040005
7    Reply to first reply 5    2 0x0000000400050007
6    Second Reply         4    1 0x000000040006
8    Reply to second comment 4    1 0x000000040008

How do I get this into an array in PHP or VB.net (I don't have a preference and use both regularly).

I want an array that looks like this (I am just specifying the ids:

array([0]
         [id]=>2
      [1]
         [id]=>4
             array([0]
                      [id]=>5
                       array([0]
                                [id]=>7
                            )
                   [1]
                      [id]=>6
                   [2]
                      [id]=>8
                   )
       )

The data is a SQL result.

Answer 1

You should use a Typed DataSet in VB .Net.

Typed DataSets will allow you to do it with almost no code, and are much easier to use than a 2-dimensional array.

To get started, create a new VB.Net project, add a Typed DataSet, and follow the instructions.

Answer 2

Note: I'm assuming, despite its being unspecified, that you need a 'children' key in addition to 'id', to contain the subarrays.

// Skip list, to hold data as well as reference to nested list later
$flat = array ();
while ($row = mysql_fetch_assoc($result))
 $flat[$row['id']] = $row;

$root = array ();
foreach ($flat as $id => $row)
{
 // Get reference to parent, or root if none set
 if (!$row['Parentid'])
  $parent =& $root;
 else
  $parent =& $flat[$row['Parentid']]['ref'];

 if (!$parent['children'])
  $parent['children'] = array (); 

 // Append new child
 $parent['children'][] = array ('id' => $id);
 // Add newly appended child to skip list
 $flat[$id]['ref'] =& end ($parent['children']);
}

// Final nested list
$nested = $root['children'];

For this to work, all parents must appear before their children in the flat list