Getting key from returned array - php

Question

I'm working in WooCommerce, but my question is related to basic PHP foreach statements.
I have a function that returns a multidimensional array. The topmost dimension, the key string is what I need. If you've familiar, $order->get_items();.
The order_item_id is stored as the key like this:
'488' => Array( /* Array stuffs */ )
That 488 is what I need. It wouldn't be a problem if the function I'm working with's foreach statement was:
foreach ($items as $k => $v)
Where I could just use $k, but it's set up as:
foreach ($items as $item)
Is there a way to set the value of the key in the array and pass it along as a parameter?
UPDATE:
Here is the function as it works.
foreach($order_items as $item) {
$product = $order->get_product_from_item($item);
$gc_enabled = get_post_meta($product->id, 'ignite_gift_enabled', true);
if ( ! $gc_enabled)
continue;
$coupon_prefix = get_post_meta($product->id, '_coupon_prefix', true);
if ( ! $coupon_prefix)
$coupon_prefix = '';
for ($x = 1; $x <= $item['qty']; $x++) {
$new_coupon = $this->adjust_voucher( $coupon_prefix, $mode, $msg_details, $order_id, $order_item_id, $product->id );
}
}
$order_items is an array of items, the keys of which I need to pass along to other functions referenced, specificaly adjust_voucher.

Answer 1

Just change the foreach syntax to be foreach($items as $key => $item). This would give you access to $key while not impacting any existing code in the loop which relies on $item.

Answer 2

Here's a quick and dirty approach. Would be expensive if you have a large array -- but otherwise it would work.
$items = $order->get_items();
array_walk($items, function(&$v, $i) { $v['id'] = $i; });
This code adds another key to the array called id and assigns it the current key value.
Requires PHP 5.4 +
Example
$arr = array(
486 => array(
'name' => 'Bob',
),
500 => array(
'name' => 'Sam',
),
);
array_walk($arr, function(&$v, $i) { $v['id'] = $i; });
print_r($arr);
Example Result
Array (
[486] => Array (
[name] => Bob
[id] => 486
)
[500] => Array (
[name] => Sam
[id] => 500
)
)

Answer 3

You can set the values in your array (if needed up the call stack)
I tried that, but there are values that are retrieved with
$item['foo']. I tried setting it to $v['foo'], but it broke.
foreach( $items as $key => &$item ) {
$item['id'] = $key;
/* $item now looks like
* [ 'id' => ...,
* ... ]
*/
} unset( $item ); //Needed otherwise references can become complicated