Add up the array values based on the same key (PHP) - php

Question

I found a case where I had to add values based on the same week.
[{"week":"30","nilai":"230"},{"week":"30","nilai":"66"},{"week":"29","nilai":"72"},{"week":"29","nilai":"225"},{"week":"28","nilai":"213"},{"week":"28","nilai":"72"},{"week":"27","nilai":"191"},{"week":"27","nilai":"60"},{"week":"26","nilai":"176"},{"week":"26","nilai":"65"},{"week":"25","nilai":"167"},{"week":"25","nilai":"57"},{"week":"24","nilai":"209"},{"week":"24","nilai":"62"},{"week":"23","nilai":"180"},{"week":"23","nilai":"88"},{"week":"22","nilai":"178"},{"week":"22","nilai":"72"},{"week":"21","nilai":"164"},{"week":"21","nilai":"42"},{"week":"20","nilai":"193"},{"week":"20","nilai":"50"},{"week":"19","nilai":"186"},{"week":"19","nilai":"56"}]
the results I expect among others are like this
week => 30,
nilai=> 296

Answer 1

<?php
$input = '[{"week":"30","nilai":"230"},{"week":"30","nilai":"66"},{"week":"29","nilai":"72"},{"week":"29","nilai":"225"},{"week":"28","nilai":"213"},{"week":"28","nilai":"72"},{"week":"27","nilai":"191"},{"week":"27","nilai":"60"},{"week":"26","nilai":"176"},{"week":"26","nilai":"65"},{"week":"25","nilai":"167"},{"week":"25","nilai":"57"},{"week":"24","nilai":"209"},{"week":"24","nilai":"62"},{"week":"23","nilai":"180"},{"week":"23","nilai":"88"},{"week":"22","nilai":"178"},{"week":"22","nilai":"72"},{"week":"21","nilai":"164"},{"week":"21","nilai":"42"},{"week":"20","nilai":"193"},{"week":"20","nilai":"50"},{"week":"19","nilai":"186"},{"week":"19","nilai":"56"}]';
$input = json_decode($input, true);
$outArr = [];
foreach ($input as $arr) {
$week = $arr['week'];
if (key_exists($week, $outArr)) {
$outArr[$week] += $arr['nilai'];
} else {
$outArr[$week] = $arr['nilai'];
}
}
//optional sort - you may remove it
ksort($outArr);
$outArr2 = [];
foreach($outArr as $week => $nilai) {
$outArr2[] = ['week' => $week, 'nilai' => $nilai];
}
var_export($outArr2);
gives result:
array (
0 =>
array (
'week' => 19,
'nilai' => 242,
),
1 =>
array (
'week' => 20,
'nilai' => 243,
),
2 =>
array (
'week' => 21,
'nilai' => 206,
),
3 =>
array (
'week' => 22,
'nilai' => 250,
),
4 =>
array (
'week' => 23,
'nilai' => 268,
),
5 =>
array (
'week' => 24,
'nilai' => 271,
),
6 =>
array (
'week' => 25,
'nilai' => 224,
),
7 =>
array (
'week' => 26,
'nilai' => 241,
),
8 =>
array (
'week' => 27,
'nilai' => 251,
),
9 =>
array (
'week' => 28,
'nilai' => 285,
),
10 =>
array (
'week' => 29,
'nilai' => 297,
),
11 =>
array (
'week' => 30,
'nilai' => 296,
),
)

Answer 2

<?php
$input = '[{"week":"30","nilai":"230"},{"week":"30","nilai":"66"},{"week":"29","nilai":"72"},{"week":"29","nilai":"225"},{"week":"28","nilai":"213"},{"week":"28","nilai":"72"},{"week":"27","nilai":"191"},{"week":"27","nilai":"60"},{"week":"26","nilai":"176"},{"week":"26","nilai":"65"},{"week":"25","nilai":"167"},{"week":"25","nilai":"57"},{"week":"24","nilai":"209"},{"week":"24","nilai":"62"},{"week":"23","nilai":"180"},{"week":"23","nilai":"88"},{"week":"22","nilai":"178"},{"week":"22","nilai":"72"},{"week":"21","nilai":"164"},{"week":"21","nilai":"42"},{"week":"20","nilai":"193"},{"week":"20","nilai":"50"},{"week":"19","nilai":"186"},{"week":"19","nilai":"56"}]';
$input = json_decode($input, true);
$outArr = [];
foreach ($input as $arr) {
$week = $arr['week'];
if (key_exists($week, $outArr)) {
$outArr[$week]['week'] += $arr['nilai'];
} else {
$outArr[$week]['nilai'] = $arr['nilai'];
}
}
print_r($outArr);
?>

Answer 3

You can do that in a single loop using array_reduce.
This solution performs a true single pass without performing any additional searches in the array. I haven't benchmarked it, but I assume it is more performant.
<?php
$values = json_decode('[{"week":"30","nilai":"230"},{"week":"30","nilai":"66"},{"week":"29","nilai":"72"},{"week":"29","nilai":"225"},{"week":"28","nilai":"213"},{"week":"28","nilai":"72"},{"week":"27","nilai":"191"},{"week":"27","nilai":"60"},{"week":"26","nilai":"176"},{"week":"26","nilai":"65"},{"week":"25","nilai":"167"},{"week":"25","nilai":"57"},{"week":"24","nilai":"209"},{"week":"24","nilai":"62"},{"week":"23","nilai":"180"},{"week":"23","nilai":"88"},{"week":"22","nilai":"178"},{"week":"22","nilai":"72"},{"week":"21","nilai":"164"},{"week":"21","nilai":"42"},{"week":"20","nilai":"193"},{"week":"20","nilai":"50"},{"week":"19","nilai":"186"},{"week":"19","nilai":"56"}]');
print_r($values);
$result = array_reduce($values, function ($carry, $item) {
$carry[$item->week] = (object) [
'week' => $item->week,
'nilai' => ($carry[$item->week]->nilai ?? 0) + $item->nilai,
];
return $carry;
}, []);
print "RESULT ... \n";
print_r($result);
Running on Repl.it at https://repl.it/repls/NauticalDamagedBytecode
This solution gives you an array that is keyed by the week number so that you can directly access them without further looping inside the array to retrieve them.
If you do not want that and if you want the array to me indexed like 0, 1, 2, 3, ... them do $result = array_values(array_reduce( ... )) or $result = array_values($result)