Assign key to array values - php

Question

i have a function that i got from stack-overflow:-
function testFunction($a, $b) {
$map = array();
foreach($a as $name => $value){
if(!isset($b[$name]) || $b[$name] != $value) {
$map[$value] = 1;
}
}
return array_keys($map);
}
$array1 = array("Peter"=>"35", "Ben"=>"21", "Joe"=>"43");
$array2 = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"57");
print_r(testFunction($array2, $array1));
here is the result i get:
Array ( [0] => 37 [1] => 57 )
because the 37 in second array is different than 21 in first array... and the 57 is different than the 43.
my question is: how can i add a key to the values? for example, I want this:
Array ("Ben"=>"37", "Joe"=>"57");

Answer 1

You can do it like below:-
<?php
function testFunction($a, $b) {
$map = array();
foreach($a as $name => $value){
if(!isset($b[$name]) || $b[$name] != $value) {
$map[$name] = $value; // make key value array
}
}
return $map;
}
$array1 = array("Peter"=>"35", "Ben"=>"21", "Joe"=>"43");
$array2 = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"57");
print_r(testFunction($array2, $array1));
Output:- https://eval.in/735195

Answer 2

Short and optimized solution using array_intersect_key and array_diff functions:
$array1 = ["Peter"=>"35", "Ben"=>"21", "Joe"=>"43"];
$array2 = ["Peter"=>"35", "Ben"=>"37", "Joe"=>"57", 'I'=>0];
// getting all $array2 items with coincident keys
$common_key_items = array_intersect_key($array2, $array1);
// getting value difference between arrays with same keys
$result = array_diff($common_key_items, $array1);
print_r($result);
The output:
Array
(
[Ben] => 37
[Joe] => 57
)