Merge two multidimensional arrays, preserve numeric keys, and combine values inside array

Question

I have two arrays and would like to combine / merge / put them together.

$arr1 = array(
    0 => array(1, 2),
    1 => array(5, 6)
);

$arr2 = array(
    0 => array(2, 3),
    1 => array(6, 7)
);    

come_together_right_now($arr1, $arr2); // the missing function?

and the result would be:

Array ( 
    [0] => Array ( 
        [0] => 1 
        [1] => 2 
        [2] => 3 
    )
    [1] => Array ( 
        [0] => 5 
        [1] => 6 
        [2] => 7 
    )

There are way too many array functions! array_merge and array_combine and the recursive alternatives seem to replace the values and they don't preserve numeric keys. How do I do this?

Related: [Merge two arrays containing objects and remove duplicate values](https://stackoverflow.com/q/10572546/2943403) — mickmackusa, Sep 13 '22 at 06:01

score 3 · Accepted Answer · answered Sep 29 '15 at 22:11

3

Assuming that they will always have the same keys!

$result = array();

foreach($arr1 as $key=>$array) {
    $result[$key] = array_merge($array, $arr2[$key]);
}

answered Sep 29 '15 at 22:11

ka_lin

9,329
6
35
56

due to the keys being numeric, duplicates are being created. Is there an array_merge I can put inside the loop that will overwrite duplicates? I edited my result set to show what I mean. – Jacob Raccuia Sep 29 '15 at 22:21
Try `array_unique(array_merge($array, $arr2[$key]));` – ka_lin Sep 29 '15 at 22:31
1

perfect for me - it keeps sub-arrays the way they are – Mel_T May 11 '17 at 08:54

score 2 · Answer 2 · answered Sep 30 '15 at 05:29

I might be late of answering this question but this might help you simply using array_map,array_merge and array_unique function like as

$result = array_map('array_unique',array_map('array_merge',$arr1,$arr2));
print_r($result);

Output

Array ( 
    [0] => Array ( 
        [0] => 1 
        [1] => 2 
        [2] => 3 
    )
    [1] => Array ( 
        [0] => 5 
        [1] => 6 
        [2] => 7 
    )

Demo

score 0 · Answer 3 · answered Sep 13 '22 at 06:17

Synchronously iterate the arrays to access their rows. Merge rows, remove duplicates, then re-index the elements.

Code: (Demo)

var_export(
    array_map(
        fn(...$rows) => array_values(array_unique(array_merge(...$rows))),
        $arr1,
        $arr2
    )
);

Merge two multidimensional arrays, preserve numeric keys, and combine values inside array

3 Answers3

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