Having an issue with array keys, undefined index - php

Question

I'm working with a couple of arrays, one of which has keys that are the productid, the value being an object that contains a doctrine entity of that product. Similarly, I have a plan with the index being the plan Id. For this for loop, I need to go through and individually set up invoices for each plan-product pair (the quantity will always be the same between them, except in cases where a user is purchasing a plan for an already owned device). Obviously this is somewhat complicated, so I'm not exactly sure how to phrase this question. An error occurs at the commented line, "Notice: Undefined Index"
for ($i = 0; $i < $totalInvoices; $i++) {
if ($i == $planQuantity[key($plans)]) {
next($plans);
}
if ($i == $productQuantity[key($products)]) {
next($products);
}
$data = array(
'planId' => key($plans),
//below here, I'm thinking at key($products) is where the error occurs
'productId' => key($products) != 0 ? key($products) : $plans[key($plans)]->getPricingTier()->getProductId(),
'userId' => $this->userId,
'paymentMethodId' => $paymentMethodId
);
if ($order['hasProduct'] || isset($order['activating'])) {
if (!isset($order['activating'])) {
$planModel->createDevicePlan($data);
$productAmount = $products[key($products)]->getAmount();
} else {
$data['deviceId'] = $order['activating']['inventoryId'];
$planModel->createDevicePlan($data, date('Y-m-d'));
$productAmount = 0;
}
} else {
$productAmount = 0;
}
if ($iteration % 5 == 0 && $order['hasShipping']) {
$invoiceShippingAmount = $billingModel->getShippingAmount($shippingOptionsId);
} else {
$invoiceShippingAmount = 0;
}
$salesData = array(
'paymentMethodsId' => $paymentMethodId,
'planAmount' => $plans[key($plans)]->getAmount(),
'planId' => key($plans),
'productAmount' => $productAmount,
'productId' => key($products),
'shippingAddressesId' => $shippingAddressId,
'shippingAmount' => $invoiceShippingAmount,
'shippingOptionsId' => $shippingOptionsId,
'transactionId' => $transactionId,
'userId' => $this->userId
);
$iteration++;
$billingModel->createInvoice($salesData);
}
Any help would be greatly appreciated.

Answer 1

Based on your comment reply, I think this will help
$plans_on_invoice = 0;
$products_on_invoice = 0;
for ($i = 0; $i < $totalInvoices; $i++) {
next($plans);
if ($plans_on_invoice == 0) {
$plans_on_invoice = $planQuantity[key($plans)];
}
plans_on_invoice--;
next($products);
if ($products_on_invoice == 0) {
$products_on_invoice = $productQuantity[key($products)];
}
products_on_invoice--;