Sum array values by attribute name - php

Question

I want to sum count values with same code.
This is my array:
$data = array(
array(
'code' => 02,
'count' => 8
),
array(
'code' => 03,
'count' => 1
),
array(
'code' => 03,
'count' => 1
),
array(
'code' => 03,
'count' => 7
),
array(
'code' => 11,
'count' => 1
),
array(
'code' => 11,
'count' => 5
),
array(
'code' => 17,
'count' => 4
),
array(
'code' => 17,
'count' => 2
),
array(
'code' => 17,
'count' => 8
)
);
Now I tried to group the array to sum the count with same code, but I think I'm wrong:
$new_data = [];
foreach($data as $k => $v){
$total = 0;
$new_data[$v['code']] = array(
'ttl' => $v['count'] + $total,
);
}
echo '<pre>';
print_r($new_data);
echo '</pre>';
What is the correct code for this? Thanks.

Answer 1

using isset will avoid undefined offset error:
$new_data = [];
foreach($data as $k => $v){
if (!isset($new_data[$v['code']]['ttl'])){
$new_data[$v['code']]['ttl'] = 0;
}
$new_data[$v['code']]['ttl'] += $v['count'];
}
print_r($new_data);

Answer 2

Assuming you want the keys in $new_data to to be the unique codes, and the values to be an an array with a key of ttl whose value is the sum of the counts for that particular code:
$new_data = [];
foreach($data as $v){
if (!array_key_exists($v['code'], $new_data)) {
$new_data[$v['code']]['ttl'] = $v['count'];
} else {
$new_data[$v['code']]['ttl'] += $v['count'];
}
}

Answer 3

I think this is what you want as output:
Array
(
[2] => Array
(
[ttl] => 8
)
[3] => Array
(
[ttl] => 9
)
[11] => Array
(
[ttl] => 6
)
[17] => Array
(
[ttl] => 14
)
)
If so, you can do minor modifications to your code such as this:
$new_data = [];
foreach ($data as $d) {
if (isset($new_data[$d['code']]['ttl'])) {
$new_data[$d['code']]['ttl'] += $d['count'];
} else {
$new_data[$d['code']]['ttl'] = $d['count'];
}
}