Merge arrays of associative arrays by shared column values [duplicate] - php

Question

This question already has answers here:
Merge two 2d arrays by shared column value
(6 answers)
Closed last month.
I want to merge two arrays based on a common column value. Here are my 2 arrays:
$array1 = [
[
"total_process_per_category" => "6",
"category_id" => "1"
],
[
"total_process_per_category" => "2",
"category_id" => "2"
]
];
$array2 = [
[
"total_pinned_per_category" => "16",
"category_id" => "1"
],
[
"total_pinned_per_category" => "4",
"category_id" => "2"
]
];
I want to merge these arrays to get:
array (
0 =>
array (
'total_process_per_category' => '6',
'total_pinned_per_category' => '16',
'category_id' => '1',
),
1 =>
array (
'total_process_per_category' => '2',
'total_pinned_per_category' => '4',
'category_id' => '2',
),
)
As you can see, the two arrays have the same key ['category_id'] and same value as well.
I want to make a result where ['total_process_per_category'] and ['total_pinned_per_category'] are placed together on the same array based on their ['category_id'] value.
I got this using a nested foreach, but it looks so ugly. Please show me a better way.

Answer 1

you can try array_reduce:
$someVariable = 'someValue';
$result = array_reduce(array_merge($array1, $array2), function ($carry, $item) use ($someVariable) {
if (isset($carry[$item['category_id']])) {
$carry[$item['category_id']] = array_merge($carry[$item['category_id']], $item);
} else {
$carry[$item['category_id']] = $item;
}
return $carry;
}, array());
var_dump($result);

Answer 2

This can be done without an "ugly nested foreach". Merge the two arrays before iterating, the group by the category_id values. After the loop, clear away the temporary first-level keys with array_values().
Code: (Demo) (array_reduce() version)
$result = [];
foreach (array_merge($array1, $array2) as $row) {
$result[$row['category_id']] = ($result[$row['category_id']] ?? []) + $row;
}
var_export(array_values($result));
Output:
array (
0 =>
array (
'total_process_per_category' => '6',
'category_id' => '1',
'total_pinned_per_category' => '16',
),
1 =>
array (
'total_process_per_category' => '2',
'category_id' => '2',
'total_pinned_per_category' => '4',
),
)

Answer 3

Do you want something like:
foreach ( $array1 as $index => $value ) {
$mergeArray[] = [ $value, $array2[$index]];
}