PHP and PayPal IPN array - php

Question

I am getting PayPal's IPN in array form like this:
$ipn = array(
'mc_gross' => '15.50',
'protection_eligibility' => 'Eligible',
'address_status' => 'confirmed',
'item_number1' => '1',
'tax' => '0.00',
'item_number2' => '2',
'payer_id' => 'XXXXXXXXXXXXX',
'address_street' => '1 Main St',
'payment_date' => '02:41:18 Nov 23, 2011 PST',
'payment_status' => 'Completed',
'charset' => 'windows-1252',
'address_zip' => '95131',
'mc_shipping' => '0.00',
'mc_handling' => '0.00',
'first_name' => 'Test',
'mc_fee' => '0.75',
'address_country_code' => 'US',
'address_name' => 'Test User',
'custom' => '',
'payer_status' => 'verified',
'business' => 'receiver#example.com',
'address_country' => 'United States',
'num_cart_items' => '2',
'mc_handling1' => '0.00',
'mc_handling2' => '0.00',
'address_city' => 'San Jose',
'payer_email' => 'payer#example.com',
'mc_shipping1' => '0.00',
'mc_shipping2' => '0.00',
'txn_id' => '8RE82733S8684874F',
'payment_type' => 'instant',
'last_name' => 'User',
'address_state' => 'CA',
'item_name1' => 'trilogy2',
'receiver_email' => 'receiver#example.com',
'item_name2' => 'trilogy1',
'payment_fee' => '0.75',
'quantity1' => '1',
'quantity2' => '1',
'receiver_id' => 'XXXXXXXXXXXXX',
'txn_type' => 'cart',
'mc_gross_1' => '5.55',
'mc_currency' => 'USD',
'mc_gross_2' => '9.95',
'residence_country' => 'US',
'transaction_subject' => 'Shopping Carttrilogy2trilogy1',
'payment_gross' => '15.50',
'' => ''
);
In this case customer has ordered only 2 items: 'item_name1' and 'item_name2'
Obviously, a customer can order X number of products and PayPal will include an 'item_nameX' in the notification data. Is there a way to go through the array and extract all names and assign them to variables so I will have something like:
$ordered_item1 = $ipn['item_name1'];
$ordered_item2 = $ipn['item_name2'];
...
$ordered_itemXYZ = $ipn['item_nameXYZ'];
Thanks for any help.

Answer 1

If you have data named with a prefix followed by a count, you should be using an array, not separate variables. To fill an array with the item information:
foreach ($ipn as $key => $value) {
if (preg_match('/(?P<field>[a-z]+)_?(?P<i>\d+)/', $key, $parts)) {
$ordered_items[(int) $parts['i']][$parts['field']] = $value;
}
}