How to group by and sum a multi-dimensional array? - php

Question

I have already seen this
stackoverflow page but it is not helping me.
I want to group by two columns and sum the values of a third column.
If the discount_id and dis_percent are the same then add the discount_value.
Here is my array:
$dis = [
[['Dis_id' => 'Dl-Dis1'], ['Dis_per' => '7.500'], ['Dis_val' => '192.75']],
[['Dis_id' => 'Dl-Dis2'], ['Dis_per' => '2.500'], ['Dis_val' => '97.88']],
[['Dis_id' => 'Dl-Dis1'], ['Dis_per' => '5.000'], ['Dis_val' => '39.90']],
[['Dis_id' => 'Dl-Dis2'], ['Dis_per' => '2.500'], ['Dis_val' => '99.90']]
];
The output that I need is:
D1-Dis1->7.5->192.75
D1-Dis1->5.0->39.9
D1-Dis2->2.5->197.78
My code looks like this:
$newarr = array();
$reverse_map = array();
foreach($dis as $idx => $entry) {
if (isset($reverse_map[$entry['Dis_id']])) {
// have we seen this name before? retrieve its original index value
$idx = $reverse_map[$entry['Dis_id']];
} else {
// nope, new name, so store its index value
$reverse_map[$entry['Dis_id']] = $idx;
}
// copy the 'constant' values
$newarr[$idx]['Dis_id'] = $entry['Dis_id'];
$newarr[$idx]['Dis_per'] = $entry['Dis_per'];
// sum the qtd_post values to whatever we previously stored.
foreach($entry['Dis_val'] as $x => $y) {
$newarr[$idx]['Dis_val'][$x] += $y;
}
}

Answer 1

This is the solution I've come up with based off of the understanding that your intended array structure was as so;
$dis = array(
array(
'Dis_id' => 'Dl-Dis1',
'Dis_per' => 7.500,
'Dis_val' => 192.75
),
...
);
It determines the solution by creating a multidimensional array where the first dimension is the Dis_id, and the second dimension is the Dis_per, and the value becomes the sum of the Dis_val;
$sums = array();
foreach ($dis as $entry) {
if (!isset($sums[$entry['Dis_id']])) {
$sums[$entry['Dis_id']] = array();
}
if (!isset($sums[$entry['Dis_id']]["{$entry['Dis_per']}"])) {
$sums[$entry['Dis_id']]["{$entry['Dis_per']}"] = 0;
}
$sums[$entry['Dis_id']]["{$entry['Dis_per']}"] += $entry['Dis_val'];
}
See this working example; https://eval.in/158661

Answer 2

As you iterate your input array, you will need to isolate the Dis_id and Dis_per values and use them as keys when storing your Dis_val.
If there no value present for a [Dis_id][Dis_per] element, then you can simply store the value. If there is a pre-existing value, you need to add the new value to the stored value. isset() is most efficient function to aid in the identification of new/existing elements in the result array.
Code: (Demo)
$dis = [
[['Dis_id' => 'Dl-Dis1'], ['Dis_per' => '7.500'], ['Dis_val' => '192.75']],
[['Dis_id' => 'Dl-Dis2'], ['Dis_per' => '2.500'], ['Dis_val' => '97.88']],
[['Dis_id' => 'Dl-Dis1'], ['Dis_per' => '5.000'], ['Dis_val' => '39.90']],
[['Dis_id' => 'Dl-Dis2'], ['Dis_per' => '2.500'], ['Dis_val' => '99.90']]
];
foreach ($dis as $group) {
$id = $group[0]['Dis_id'];
$per = $group[1]['Dis_per'];
if (!isset($result[$id][$per])) {
$result[$id][$per] = $group[2]['Dis_val'];
} else {
$result[$id][$per] += $group[2]['Dis_val'];
}
}
var_export($result);
Output:
array (
'Dl-Dis1' =>
array (
'7.500' => '192.75',
'5.000' => '39.90',
),
'Dl-Dis2' =>
array (
'2.500' => 197.78,
),
)