Array reduce with associative array - php

Question

I have an array like this
$filter_array = Array
(
[0] => Array
(
[fv_id] => 1
[fv_value] => Red
[filter_id] => 1
[filter_name] => Color
)
[1] => Array
(
[fv_id] => 2
[fv_value] => Blue
[filter_id] => 1
[filter_name] => Color
)
)
I would like to reduce the array by having filter_name and filter_id on top of array which is similar for all arrays.
$newArray = array_reduce($filter_array,function($carry,$item){
$allFilterValues[] = array(
'fv_id' => $item['fv_id'],
'fv_value' => $item['fv_value'],
);
$formated_array = array(
'filter_id' => $item['filter_id'],
'filter_name' => $item['filter_name'],
'filter_values' => $allFilterValues
);
return $formated_array;
});
But I am just getting the last array iterations value on filter_values
Array
(
[filter_id] => 1
[filter_name] => Color
[filter_values] => Array
(
[0] => Array
(
[fv_id] => 2
[fv_value] => Blue
)
)
)
But I want the array be like this.
Array
(
[filter_id] => 1
[filter_name] => Color
[filter_values] => Array
(
[0] => Array
(
[fv_id] => 1
[fv_value] => Red
),
[1] => Array
(
[fv_id] => 2
[fv_value] => Blue
)
)
)

Answer 1

On each iteration of array_reduce callback function must return current $carry value:
$newArray = array_reduce($filter_array,function($carry,$item){
// create key so as to distinct values from each other
$key = $item['filter_id'] . '-' . $item['filter_name'];
// check if created key exists in `$carry`,
// if not - we init it with some data
if (empty($carry[$key])) {
$carry[$key] = [
'filter_id' => $item['filter_id'],
'filter_name' => $item['filter_name'],
'filter_values' => []
];
}
// add values to `filter_values`
$carry[$key]['filter_values'][] = [
'fv_id' => $item['fv_id'],
'fv_value' => $item['fv_value'],
];
return $carry;
}, []);
// if you want to reindex `$newArray` from 0:
$newArray = array_values($newArray);
Update: if and only if in your $filter_array values of 'filter_id' and 'filter_name' are always the same you can simplify your code:
$newArray = [];
$first = true;
foreach ($filter_array as $item) {
if ($first) {
$first = false;
$newArray = [
'filter_id' => $item['filter_id'],
'filter_value' => $item['filter_name'],
'filter_values' => []
];
}
$newArray['filter_values'][] = [
'fv_id' => $item['fv_id'],
'fv_value' => $item['fv_value'],
];
}
echo'<pre>',print_r($newArray),'</pre>';