Merge arrays in an array and add values - php

Question

I need to take an array like this:
Array
(
[0] => Array
(
[county_code] => 54045
[count] => 218
)
[1] => Array
(
[county_code] => 54045
[count] => 115
)
[2] => Array
(
[county_code] => 54051
[count] => 79
)
)
And merge all arrays with the same county_code adding the count, like this:
Array
(
[0] => Array
(
[county_code] => 54045
[count] => 333
)
[1] => Array
(
[county_code] => 54051
[count] => 79
)
)
There will be multiple instances of multiple county codes.
Can anyone point me in the right direction?

Answer 1

Try this out:
// your example array
$array = [
[
"county_code" => 54045,
"count" => 218
],
[
"county_code" => 54045,
"count" => 115
],
[
"county_code" => 54051,
"count" => 79
]
];
// intrim step to collect the count.
$intrimArray = [];
foreach( $array as $data ){
$countyCode = $data["county_code"];
if (!$intrimArray[$countyCode]) {
$intrimArray[$countyCode] = $data["count"];
} else {
$intrimArray[$countyCode] = $intrimArray[$countyCode] + $data["count"];
}
}
// build the final desired array using interim array.
$finalArray = [];
foreach($intrimArray as $countyCode => $totalCount) {
array_push($finalArray, [
"county_code" => $countyCode,
"count" => $totalCount
]);
}
var_dump($finalArray);

Answer 2

As promised:
<?php
$initial_array = [
['country_code' => 54045, 'count' => 218],
['country_code' => 54045, 'count' => 115],
['country_code' => 54051, 'count' => 79],
];
$synth = [];
foreach ($initial_array as $sa) { # $sa: subarray
if (!isset($synth[$sa['country_code']])) {
$synth[$sa['country_code']] = 0;
}
$synth[$sa['country_code']] += $sa['count'];
}
print_r($synth); # Synthesis array: keys are country codes, values are cumulative counts.
# If you need the same format for both the initial and synthesis arrays, then continue with this:
$synth2 = [];
foreach ($synth as $k => $v) {
$synth2[] = ['country_code' => $k, 'count' => $v];
}
print_r($synth2);
?>
A fiddle for this code: https://3v4l.org/M8tkb
Best regards