如何使用if条件对数组值求和

Question

I got the following array from my code.

foreach($JobworkMaterialJson as $key => $value) { 
    $decode = json_decode($value->jobcard_jobwork_json); 
}

by the print_r($decode), I got following result now I want to sum values which id is same. e.g. id=6 qty would be 25. help will be highly appreciated. Thanks

<pre>Array(
[0] => stdClass Object
    (
        [id] => 9
        [qty] => 5
    )
)
</pre><pre>Array
(
[0] => stdClass Object
    (
        [id] => 6
        [qty] => 10
    )

[1] => stdClass Object
    (
        [id] => 7
        [qty] => 5
    )
) 
</pre><pre>Array
(
[0] => stdClass Object
    (
        [id] => 6
        [qty] => 15
    )
)
</pre>

Answer 1

You can do this using an associative array (a dictionary) to keep track of the counts. Iterate over all the inputs and update the dictionary.

Example code

<?php
$items = array(); // this should be the array you refer to in your question.

$dictionary = array();
foreach($items as $item) {
    if(array_key_exists($item->id, $dictionary)) {
        $dictionary[$item->id] += $item->qty;
    } else {
        $dictionary[$item->id] = $item->qty;
    }
}

$dictionary now contains the sums. For example $dictionary['6'] will return 25.