iterate through 3 dimensional array php

Question

I have created a 3 dimensional array (Fig 1) from a MySQL query (fig 2). The top level is [Expense_ID] and the next level up is [Participant_ID]. There can be multiple Participant_ID's for each Expense_ID.

Qu 1) Although the data is all repeated at the bottom level of the array, please could someone tell me how I can iterate through this array as it is (at each level) to echo out the structure as per the original data (if I can echo it out, then I can perform the calculations I need to do). ie in the echo statement, [Expense_ID] would be taken from the top level of the array, [Participant_ID] would be taken from level 2 and the remaining 3 fields would be taken from the bottom level.

Qu 2) I don't know if this is the best array structure. The code I used to get to this array is shown in fig 3. How could I change this so that level one shows as [0] => 86 and level 2 is [0] => 130, 1 => 135 This might be easier to work with.

Qu 2a) How then would I iterate through the array if it is in this format?

Any help would be much appreciated.

Fig 1: Array Structure

Array
(
    [86] => Array
        (
            [130] => Array
                (
                    [Expense_ID] => 86
                    [Expense_Description] => Item1
                    [Total_Amount] => 3000.00
                    [Expense_Payer_ID] => 134
                    [Participant_ID] => 130
                )

            [135] => Array
                (
                    [Expense_ID] => 86
                    [Expense_Description] => Item1
                    etc.

Fig 2

Fig 3

    $result = array();
    while ($row = mysql_fetch_array($Exps)){
        $Exp_ID    = $row['Expense_ID'];    
        $Participant_ID = $row['Participant_ID'];
        $result[$Exp_ID][$Participant_ID] = array(                   
            'User_ID' => $row['User_ID'],
            'Expense_ID' => $row['Expense_ID'],
             etc.
        );
    }

Answer 1

I'm not sure I understand what you are asking but I think a simple foreach loop will do the trick.

foreach ($result as $id => $participants) {            

    // here your Expense_ID == $id            

    foreach ($participants as $pid => $value) {            

        // here Participant_ID == $pid
        // 
        // Total_Amount == $value['Total_Amount']
        // Expense_Description == $value['Expense_Description']
        // ....
    }
}

Hope this can help.