Combine two arrays into a single array based on a common column value [duplicate]

Question

I am trying to combine two arrays while respecting their shared value.

$array1 = array(
    array("id" => "1","name"=>"John"),
    array("id" => "2","name"=>"Peter"),
    array("id" => "3","name"=>"Tom"),
    array("id" => "12","name"=>"Astro")
);

$array2 = array(
    array("id" => "1","second_name"=>"Lim"),
    array("id" => "2","second_name"=>"Parker"),
    array("id" => "3","second_name"=>"PHP")
);

My expected output:

$result = array(
    array("id" => "1","name"=>"John","second_name"=>"Lim"),
    array("id" => "2","name"=>"Peter","second_name"=>"Parker"),
    array("id" => "3","name"=>"Tom","second_name"=>"PHP"),
    array("id" => "12","name"=>"Astro")
);

I have made a try by

$arraycomb = array_unique(array_merge($array1,$array2), SORT_REGULAR);

My output is:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => John
        )

    [1] => Array
        (
            [id] => 2
            [name] => Peter
        )

    [2] => Array
        (
            [id] => 3
            [name] => Tom
        )

    [3] => Array
        (
            [id] => 12
            [name] => Astro
        )

    [4] => Array
        (
            [id] => 1
            [second_name] => Lim
        )

    [5] => Array
        (
            [id] => 2
            [second_name] => Parker
        )

    [6] => Array
        (
            [id] => 3
            [second_name] => PHP
        )

)

How can I combine the key value inside same array? or how can I bring the expected output?

Note: I am trying for value instead of key ref: PHP Array Merge two Arrays on same key

what would be the size of the final array. equal to the first array or second array?? — Sougata Bose
– Sougata Bose, Commented Nov 6, 2014 at 10:50

Kevin · Accepted Answer · 2014-11-06 10:49:20Z

5

Alternatively, you could use a foreach in this case then merge them if they share the same id key

With using reference &

foreach($array1 as &$value1) {
    foreach ($array2 as $value2) {
        if($value1['id'] == $value2['id']) {
            $value1 = array_merge($value1, $value2);
        }
    }
}

echo '<pre>';
print_r($array1);

edited Nov 6, 2014 at 10:49

answered Nov 6, 2014 at 10:38

Kevin

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9 Comments

DonOfDen Over a year ago

@AresDraguna and AresDraguna Thank you.. for the help and making me understand.. The logic provided by sgt help me to get the expected output..

DonOfDen Over a year ago

@AresDraguna Which answer will take less time during execution? When I accept the answer other might try and use the code so..

Ares Draguna Over a year ago

@TomPHP :)) how come? so if you have array("id" => "12","name"=>"Astro") on the 4th position in the first array and array("id" => "7","second_name"=>"Lim"), on the 4th position in the second one, with different id's you want to merge or map them? They have different id's!! I don't understand...

DonOfDen Over a year ago

@AresDraguna if the ID is different Then the array should be just merger tot he result array... Check the Expected OutPut Array for better understanding.

Ares Draguna Over a year ago

of course... I am not judging what he wants to achieve, I am just saying that, in my point of view, the logic is wrong... I am a "purebred" PHP programmer and for me things HAVE GOT to be logic, otherwise I cannot code :)) this is one of my biggest weaknesses in life

|

Sougata Bose · Accepted Answer · 2014-11-06 10:54:54Z

3

You can use array_map() for this. Try this -

function modifyArray($a, $b)
{
    if (!empty($a) && !empty($b)) {
        return array_merge($a, $b);
    } else if (!empty($a) && empty($b)) {
        return $a;
    }  else if (empty($a) && !empty($b)) {
        return $b;
    }
}

$new = array_map("modifyArray", $array1, $array2);
var_dump($new);

It will generate the new array will all the values in both arrays.if the first array's element is empty then the second array will be merged and vice-versa.

edited Nov 6, 2014 at 10:54

answered Nov 6, 2014 at 10:45

Sougata Bose

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2 Comments

Sougata Bose Over a year ago

this solution would only help if the ids are not important as when they get merged the ids will overlap.

DonOfDen Over a year ago

Yup! I added an alternative key to have ID for reference.. Thank you!!

mickmackusa · Accepted Answer · 2022-09-19 21:11:13Z

Assign temporary first level keys to your first array to aid in identifying rows. Then loop the second array and append the desired column value to the appropriate group. Re-index the array after looping with array_values().

Code: (Demo)

$result = array_column($array1, null, 'id');
foreach ($array2 as $row) {
    $result[$row['id']]['second_name'] = $row['second_name'];
}
var_export(array_values($result));

This is a more direct approach than brute force scanning arrays with nested loops.

If all ids in the second array exist in the first array, then the following simpler line can be written inside the body of the foreach().

$result[$row['id']] += $row;

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