Merge array by id and sum amount - php

Question

I'm trying to merge and calc only by choosen key. For example I have the following array:
$array = array();
$array['Fruit'][] = ['id' => 17, 'name' => 'seasonal fruit', 'type' => 'Fruit', 'measurement' => '', 'amount' => 2];
$array['Fruit'][] = ['id' => 17, 'name' => 'seasonal fruit', 'type' => 'Fruit', 'measurement' => '', 'amount' => 1];
$array['protein'][] = ['id' => 16, 'name' => 'soy yogurt', 'type' => 'protein', 'measurement' => '', 'amount' => 2];
$array['protein'][] = ['id' => 18, 'name' => 'oilseed', 'type' => 'protein', 'measurement' => 'grip', 'amount' => 2];
$array['protein'][] = ['id' => 18, 'name' => 'oilseed', 'type' => 'protein', 'measurement' => 'grip', 'amount' => 1];
$array['lipid'][] = ['id' => 19, 'name' => 'coconut powder', 'type' => 'lipid', 'measurement' => 'Tablespoon', 'amount' => 2];
$array['lipid'][] = ['id' => 20, 'name' => 'chocolate powder', 'type' => 'lipid', 'measurement' => 'Tablespoon', 'amount' => 2];
$array['lipid'][] = ['id' => 38, 'name' => 'chocolate square', 'type' => 'lipid', 'measurement' => '', 'amount' => 1];
Final output should look like this :
Array (
[0] => Array (
[id] => 17
[name] => seasonal fruit
[type] => Fruit
[measurement] =>
[amount] => 3
)
[1] => Array (
[id] => 16
[name] => soy yogurt
[type] => protein
[measurement] =>
[amount] => 2
)
[2] => Array (
[id] => 18
[name] => oilseed
[type] => protein
[measurement] => grip
[amount] => 3
)
[3] => Array (
[id] => 19
[name] => coconut powder
[type] => lipid
[measurement] => Tablespoon
[amount] => 2
)
[4] => Array (
[id] => 20
[name] => chocolate powder
[type] => lipid
[measurement] => Tablespoon
[amount] => 2
)
[5] => Array (
[id] => 38
[name] => chocolate square
[type] => lipid
[measurement] =>
[amount] => 1
)
)
I tried the following :
$courses = [];
foreach ($array as $key => $item) {
if (!key_exists($key, $courses)) {
$courses[$key] = [];
}
foreach ($item as $row) {
$id = $row['id'];
if (!key_exists($id, $courses[$key])) {
$courses[$key][$id] = $row;
continue;
}
$r = &$courses[$key][$id];
$r['amount'] += $row['amount'];
}
}
Output:
Array (
[Fruit] => Array (
[17] => Array (
[id] => 17
[name] => seasonal fruit
[type] => Fruit
[measurement] =>
[amount] => 3
)
)
[protein] => Array (
[16] => Array (
[id] => 16
[name] => soy yogurt
[type] => protein
[measurement] =>
[amount] => 2
)
[18] => Array (
[id] => 18
[name] => oilseed
[type] => protein
[measurement] => grip
[amount] => 3
)
)
[lipid] => Array (
[19] => Array (
[id] => 19
[name] => coconut powder
[type] => lipid
[measurement] => Tablespoon
[amount] => 2
)
[20] => Array (
[id] => 20
[name] => chocolate powder
[type] => lipid
[measurement] => Tablespoon
[amount] => 2
)
[38] => Array (
[id] => 38
[name] => chocolate square
[type] => lipid
[measurement] =>
[amount] => 1
)
)
)

Answer 1

You were not far off, but everything you are interested in ins inside the inner foreach, that way you dont get the Fruit and Protien etc involved
$courses = [];
foreach( $array as $sub){
foreach ($sub as $item) {
if ( array_key_exists($item['id'], $courses) ) {
// dup, so just add to the amount
$courses[$item['id']]['amount'] += $item['amount'];
} else {
//New entry
$courses[$item['id']] = $item;
}
}
}
// if its important to have indexes starting at 0 for the result
$courses = array_values($courses);