PHP merge array of arrays and increment values?

Question

I have the following array structure:

[0] => Array
    (
        [name] => Spinat boller
        [amount] => 3
        [category] => Bløddej og Boller
        [unit_amount] => 15
    )

[1] => Array
    (
        [name] => Bedste boller
        [amount] => 15
        [category] => Bløddej og Boller
        [unit_amount] => 15
    )

[2] => Array
    (
        [name] => Grov boller
        [amount] => 15
        [category] => Bløddej og Boller
        [unit_amount] => 15
    )

I have multiple of these arrays, and i would like to merge them on the AMOUNT KEY ONLY. That means if i have another array containing this:

[0] => Array
    (
        [name] => Spinat boller
        [amount] => 2
        [category] => Bløddej og Boller
        [unit_amount] => 15
    )

And i merge it, it would show this:

[0] => Array
    (
        [name] => Spinat boller
        [amount] => 5
        [category] => Bløddej og Boller
        [unit_amount] => 15
    )

Obviously i could traverse this manually, but i was hoping i could utilize the PHP Merge function somehow, but not sure how to go about it.

Thanks everyone!

* Edit 1 * If i just do the array_merge function, it simply appends it all together, so i go from:

[0] => Array
(
    [name] => Spinat boller
    [amount] => 3
    [category] => Bløddej og Boller
    [unit_amount] => 15
)

to:

[0] => Array
(
    [name] => Spinat boller
    [amount] => 3
    [category] => Bløddej og Boller
    [unit_amount] => 15
)
[0] => Array
(
    [name] => Spinat boller
    [amount] => 2
    [category] => Bløddej og Boller
    [unit_amount] => 15
)

but i want:

[0] => Array
(
    [name] => Spinat boller
    [amount] => 3
    [category] => Bløddej og Boller
    [unit_amount] => 15
)

[0] => Array ( [name] => Spinat boller [amount] => 5 [category] => Bløddej og Boller [unit_amount] => 15 )

Notice how the amount is now 5 (the other arrays had 2 and 3). Everything else is the same and matches, ONLY the amount gets added and incremented.

`array_merge` function not working? http://php.net/manual/ru/function.array-merge.php for example use: `$res = array_merge($array1,$array2,$array3 ... and etc params arrays)` — Naumov, Apr 19 '16 at 15:34
I want to look at the name, and increment the amount. So if i have 2 with the same name, it increments the amount ONLY and leaves all others be, since they will also match. Everything will match, except amount which might be different, so yes, unit amount and category is always the same for that name (name is unique). — J.B.J., Apr 19 '16 at 16:14

score 1 · Answer 1 · answered Apr 20 '16 at 18:08

So I gave it some thought, to see if it's possible to do it in a single expression.

You have to combine quite a few functions, but the behaviour is the same as with manual iteration. The result of this functional approach looks like this:

$result = array_values(
    array_merge(
        ...array_reverse(
            array_map(function ($arr) {
                return array_combine(
                    array_column($arr, 'name'),
                    array_values($arr)
                );
            }, [$arr1, $arr2, $arr3])
        )
    )
);

Though it can be done, I sticking with the iteration approach would be best for maintainability reasons:

$tmp = [];

foreach ($arrays as $arr) {
    foreach ($arr as $elem) {
        if (!isset($tmp[$elem['name']])) {
            $tmp[$elem['name']] = $elem;
        }
    }
}

$result = array_values($tmp);

PHP merge array of arrays and increment values?

1 Answers1