How to merge two arrays with same id? [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 last month.
first arrays has two properties:
id, text
second array has two properties
id, count
How to combine these into one array by id where the new array will have three properties:
id
text
count
First array:
array(2) {
[0]=>
object(stdClass)#351 (2) {
["id"]=>
string(1) "1"
["text"]=>
string(5) "tree"
}
[1]=>
object(stdClass)#348 (2) {
["id"]=>
string(1) "2"
["text"]=>
string(8) "house"
}
second array:
array(2) {
[0]=>
object(stdClass)#351 (2) {
["id"]=>
string(1) "1"
["count"]=>
string(5) "3"
}
[1]=>
object(stdClass)#348 (2) {
["id"]=>
string(1) "2"
["count"]=>
string(8) "4"
}
I tried:
array_merge_recursive, array_merge where these only merge the two arrays together into one long array.
Expected output with above arrays:
array(2) {
[0]=>
object(stdClass)#351 (2) {
["id"]=>
string(1) "1"
["count"]=>
string(5) "3"
string(1) "1"
["text"]=>
string(5) "tree"
}
[1]=>
object(stdClass)#348 (2) {
["id"]=>
string(1) "2"
["count"]=>
string(8) "4"
string(1) "2"
["text"]=>
string(8) "house"
}

Answer 1

You could write a simple function that would merge the properties of the object in the second array if it matches the id of the object in the first array:
function obj_array_merge( $a1, $a2 ) {
$newAry = [];
foreach( $a1 as $idx => $obj1 ) {
// Clone object to prevent alterations to object in $a1
$newAry[$idx] = clone $obj1;
foreach($a2 as $obj2) {
/**
** If id property of both objects match,
** copy properties from second array object
** to new object (clone of first array object).
*/
if( $newAry[$idx]->id === $obj2->id ) {
foreach($obj2 as $prop => $val) {
$newAry[$idx]->$prop = $val;
}
}
}
}
return $newAry;
}
// To run:
$mergedArray = obj_array_merge( $array1, $array2 );
However, note that this is not going to be fast. With a large number of objects it can get quite slow since it has to iterate over both arrays to check for matches. It will also overwrite properties that exist in the new array object with that of the second array object (you didn't specify if that was an issue).