Merge rows between two arrays of objects based on column value [duplicate] - php

Question

This question already has answers here:
Merging and group two arrays containing objects based on one identifying column value
(4 answers)
Closed 5 months ago.
After I merged two arrays like this array_merge($array1, $array2);, it becomes like this:
array(10) {
[0]=>
object(stdClass) (2) {
["id"]=>
string(1) "1"
["text"]=>
string(5) "one"
}
[1]=>
object(stdClass) (2) {
["id"]=>
string(1) "2"
["text"]=>
string(8) "two"
}
[2]=>
object(stdClass) (2) {
["id"]=>
string(1) "3"
["text"]=>
string(4) "three"
}
[3]=>
object(stdClass) (2) {
["id"]=>
string(1) "4"
["text"]=>
string(8) "four"
}
[4]=>
object(stdClass) (2) {
["id"]=>
string(1) "5"
["text"]=>
string(3) "five"
}
[5]=>
object(stdClass) (2) {
["id"]=>
string(1) "1"
["unit"]=>
string(1) "0"
}
[6]=>
object(stdClass) (2) {
["id"]=>
string(1) "2"
["unit"]=>
int(0)
}
[7]=>
object(stdClass) (2) {
["id"]=>
string(1) "3"
["unit"]=>
int(0)
}
[8]=>
object(stdClass) (2) {
["id"]=>
string(1) "4"
["unit"]=>
string(1) "0"
}
[9]=>
object(stdClass) (2) {
["id"]=>
string(1) "5"
["unit"]=>
int(1)
}
}
Which means both arrays are literally merged. But what I wanted is since both arrays has common property called id and same value for it, it should become like:
array(2) {
[0]=>
object(stdClass) (2) {
["id"]=>
string(1) "1"
["text"]=>
string(5) "one"
["unit"]=>
int(0)
}
[1]=>
object(stdClass) (2) {
["id"]=>
string(1) "2"
["text"]=>
string(8) "two"
["unit"]=>
int(2)
}
}
Note that array1 has id, text while array2 has id and unit.
I did refer here as tried the first answer which suggest to use array_map(), but for me I'm getting error saying argument 1 is not an array.
Combine two arrays into a single array based on a common column value
EDIT:
tried this (doesn't work):
$array1 = array_walk($array1, function(&$value) { $value = (array) $value; })
$array2 = array_walk($array2, function(&$value) { $value = (array) $value; })
function modifyArray($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);

Answer 1

Merging objects is noticeably more tedious than arrays. I'd be tempted to convert the array of objects to an array or arrays in my own project, but I won't for this solution.
Unlike arrays which can enjoy array_merge() or the union operator, objects need to be pushed in manually.
I am temporarily grouping data by using the id values as first level keys in the loop, then optionally sorting by those keys, then re-indexing the output to remove the temporary keys.
Code: (Demo):
$output = [];
foreach ($poorly_merged as $object) {
if (!isset($output[$object->id])) {
$output[$object->id] = $object;
} else {
foreach ($object as $property => $value) {
$output[$object->id]->{$property} = $value;
}
}
}
ksort($output); // optionally order by ids
var_export(array_values($output));
Or:
$output = [];
foreach ($poorly_merged as $object) {
if (!isset($output[$object->id])) {
$output[$object->id] = (object)[];
}
foreach ($object as $property => $value) {
$output[$object->id]->{$property} = $value;
}
}
ksort($output); // optionally order by ids
var_export(array_values($output));
Better practice would be not to merge your twp input arrays to form the $poorly_merged array. You could use iterate the second array of objects and add that data into the first -- this would be a more direct solution.