show difference between of two price list

Question

I have history list of product price(order by created_at) like this:

Array
(
    [0] => stdClass Object
        (
            [id] => 1
            [product_id] => 49
            [price] => 14520000.0000
            [created_at] => 1592501154
        )

    [1] => stdClass Object
        (
            [id] => 2
            [product_id] => 49
            [price] => 14000000.0000
            [created_at] => 1592587554
        )

    [2] => stdClass Object
        (
            [id] => 4
            [product_id] => 49
            [price] => 14800000.0000
            [created_at] => 1592673954
        )

    [3] => stdClass Object
        (
            [id] => 5
            [product_id] => 49
            [price] => 10000000.0000
            [created_at] => 1592760354
        )

    [4] => stdClass Object
        (
            [id] => 6
            [product_id] => 49
            [price] => 14000000.0000
            [created_at] => 1592846754
        )

    [5] => stdClass Object
        (
            [id] => 7
            [product_id] => 49
            [price] => 14000000.0000
            [created_at] => 1592933154
        )

    [6] => stdClass Object
        (
            [id] => 8
            [product_id] => 49
            [price] => 14000000.0000
            [created_at] => 1593019554
        )

)

Now for show data in table I listed price using foreach method like this:

   <?php foreach($product_prices_list as $product_price_list):?>
     <tr>
         <td><?= esc($product_price_list->created_at);?></td>
         <td class="text-center"><?= esc(number_format($product_price_list->price));?></td>
         <td class="text-center"></td> //show difference between of two price
     </tr>
   <?php endforeach;?>

I can see true output in table but I need to show difference between of two price in the third column like this picture:

how do can i show difference between of two price in my list?!

Answer 1

You just need to compare the current price property to the price from the previous object in the array?

Something like this should work:

<?php foreach($product_prices_list as $key => $product_price_list):?>
    <tr>
        <td><?= esc($product_price_list->created_at);?></td>
        <td class="text-center"><?= esc(number_format($product_price_list->price));?></td>
        <td class="text-center"><?= (!empty($product_prices_list[$key - 1])) ? $product_prices_list[$key + 1]->price - $product_price_list->price: 0; ?></td> //show difference between of two price
    </tr>
<?php endforeach;?>