Creating multidimensional array from existing arrays with variable variables

I'm creating a class function which accepts a mysql query result and returns a multidimensional array where the first array pointer is the table column and the second pointer is a numeric indicator of its position in the MySQL data.

Eg the table has the following columns:

Groupname
Groupid
Groupurl

And the way I want to call this is:

$arrayname[groupname][1];

I have formed 2 arrays already which are:

$colnames which contains all columns from the specific mysql query and

$$colname which is a variable variable of the column name containing all the data in each column. Eg: $groupurl is an array with all the data from that column.

I can't seem to get a loop to join the arrays as a multidimensional object and while I can manually do this for a specific table, it's a class function, and the variable variable part is breaking me =\

================ Thanks to IMSoP who gave me the idea, the solution is ==================

$result in the function is a successful MySQL Query on a table.

function tableAsMatrix($result)
{
    //declare $results as array for use in loop
    $results = array();

    //this gets all the col names and sets them as $colnames[]
    while( $cols = $result->fetch_field() )
    {
        $colnames[] = $cols->name;
    }

    //this loops through and assigns all cols as multidimensional $results[colname][id]
    foreach ($colnames as $fields)
    {
        while ($row = $result->fetch_array(MYSQLI_ASSOC))
        {
           foreach($colnames as $field)
           {
               $results[$field][] = $row[$field];
           }
        }
    }

    //return to object
    return $results;

}