Merging and group two arrays containing objects based on one identifying column value

Question

I have a trouble regarding merging arrays by specific scenario. Searching for similar cases gave no results here. To understand clearly what is my requirements, please look at the next example:

$array1 = [
    (object) ['call_date' => '2013-10-22 00:00:00', 'first_amount' => 10],
    (object) ['call_date' => '2013-10-23 00:00:00', 'first_amount' => 20],
];

$array2 = [
    (object) ['call_date' => '2013-10-22 00:00:00', 'second_amount' => 30],
    (object) ['call_date' => '2013-10-24 00:00:00', 'second_amount' => 40],
];

What I need as the output:

Array
(
    [0] => stdClass
        (
            [call_date] => 2013-10-22 00:00:00
            [first_amount] => 10
            [second_amount] => 30
        )

    [1] => stdClass
        (
            [call_date] => 2013-10-23 00:00:00
            [first_amount] => 20
        )

    [2] => stdClass
        (
            [call_date] => 2013-10-24 00:00:00
            [second_amount] => 40
        )
)

So as you can see merging goes by call_date. Items from the first and the second array which are under the date 2013-10-22 00:00:00 was combined, item from the second array under the date 2013-10-24 00:00:00 was appended.

Tried a lot of combinations of array_merge, array_udiff, array_merge_recursive, array_map, but nothing helped.

Answer 1

Simple scenario:

1. change array keys
2. merge recursive
3. map merged elements back to object (stdClass)

Example:

//change key
$workFirstArray = array_combine(
    array_map(function($object) { return $object->call_date;}, $firstArray), $firstArray
);
$workSecondArray = array_combine(
    array_map(function($object) { return $object->call_date;}, $secondArray), $secondArray
);

//map merged elements back to StdClass
$result = array_map(function($element) {
        if(is_array($element)) {
            $element['call_date'] = end($element['call_date']);
            $element=(object)$element;
        }
        return $element;
    },
    array_merge_recursive($workFirstArray, $workSecondArray)
);

output:

Array
(
    [0] => stdClass Object
        (
            [call_date] => 2013-10-22 00:00:00
            [first_amount] => 10
            [second_amount] => 40
        )

    [1] => stdClass Object
        (
            [call_date] => 2013-10-23 00:00:00
            [second_amount] => 30
        )

    [2] => stdClass Object
        (
            [call_date] => 2013-10-24 00:00:00
            [second_amount] => 40
        )

)