merge 2 array with different number of keys - php

Question

I have 2 arrays
$arr1 = Array
(
[REG1] => 94
[REG3] => 45
)
$arr2 =Array
(
[0] => REG1
[1] => REG2
[2] => REG3
[3] => REG4
)
I have to loop 2 arrays and I would like a result in one array like this:
Array(
[0] => Array(
[REG1] => 94
)
[1] => Array(
[REG2] =>
)
[2] => Array(
[REG3] => 45
)
[3] => Array(
[REG4] =>
)
)
But for the instand I can not do what I want, here is where I am:
private function mergeData($arr1, $arr2){
$result = array_map(function($v1, $v2){
$t[$v1] = $v2;
return $t;
}, $arr2, $arr1);
return $result;
}
output:
Array(
[0] => Array(
[REG1] => 94
)
[1] => Array(
[REG2] =>45
)
[2] => Array(
[REG3] =>
)
[3] => Array(
[REG4] =>
)
)
I cannot correctly put the bone values with the right keys.
I tried with array_merge_recursive but also failed.
Thanks for your help

Answer 1

$arr3 = array_fill_keys( $arr2, '' );
creates an array containing the values of $arr2 as keys with as value an empty string.
$arr3 =Array
(
[REG1] => ''
[REG2] => ''
[REG3] => ''
[REG4] => ''
)
After that just merge.
$result = array_merge ( $arr3, $arr1 );

Answer 2

Another option would be to use the array_map function and map key with the corresponding values, if any:
$arr1 = [
'REG1' => 94,
'REG3' => 45
];
$arr2 = [
'REG1',
'REG2',
'REG3',
'REG4'
];
$result = array_map(function($item) use($arr1){
return [$item => isset($arr1[$item]) ? $arr1[$item] : ""];
},$arr2);
This will return:
Array
(
[0] => Array
(
[REG1] => 94
)
[1] => Array
(
[REG2] =>
)
[2] => Array
(
[REG3] => 45
)
[3] => Array
(
[REG4] =>
)
)

Answer 3

Using a loop:
<?php
$arr1 = [
'REG1' => 94,
'REG3' => 45
];
$arr2 = [
'REG1',
'REG2',
'REG3',
'REG4'
];
$result = $arr2;
foreach($result as &$v)
$v = [$v => $arr1[$v] ?? null];
unset($v);
var_export($result);
Output:
array (
0 =>
array (
'REG1' => 94,
),
1 =>
array (
'REG2' => NULL,
),
2 =>
array (
'REG3' => 45,
),
3 =>
array (
'REG4' => NULL,
),
)