Neelkanth Kaushik Neelkanth Kaushik - 5 months ago 9
PHP Question

Grouping multidimensional PHP array and calculating sum of a particular key for each arrays element

I had an array which had data about all projects.

I needed to group the array by 'year_actual' element.

I have successfully done this grouping using a php function “array_group_by” which is available here: https://gist.github.com/mcaskill/baaee44487653e1afc0d

Here is my grouped array which I assigned to a variable: $projects_grouped_by_year

Array
(
[2016] => Array
(
[0] => Array
(
[id] => 1
[project_name] => P1
[project_capacity] => 100
[year_actual] => 2016
[companies] => Array
(
[0] => Array
(
[id] => 1
[project_id] => 1
[company_type] => C1
[capacity_share] => 12
[project_year] => 2016
)

[1] => Array
(
[id] => 2
[project_id] => 1
[company_type] => C2
[capacity_share] => 14
[project_year] => 2016
)

)

)

[1] => Array
(
[id] => 2
[project_name] => P2
[project_capacity] => 200
[year_actual] => 2016
[companies] => Array
(
[0] => Array
(
[id] => 3
[project_id] => 2
[company_type] => C2
[capacity_share] => 15
[project_year] => 2016
)

[1] => Array
(
[id] => 4
[project_id] => 2
[company_type] => C1
[capacity_share] => 16
[project_year] => 2016
)

)

)

)

[2014] => Array
(
[0] => Array
(
[id] => 3
[project_name] => P3
[project_capacity] => 300
[year_actual] => 2014
[companies] => Array
(
[0] => Array
(
[id] => 5
[project_id] => 3
[company_type] => C1
[capacity_share] => 20
[project_year] => 2014
)

[1] => Array
(
[id] => 6
[project_id] => 3
[company_type] => C2
[capacity_share] => 22
[project_year] => 2014
)

)

)

[1] => Array
(
[id] => 4
[project_name] => P4
[project_capacity] => 400
[year_actual] => 2014
[companies] => Array
(
[0] => Array
(
[id] => 7
[project_id] => 4
[company_type] => C2
[capacity_share] => 11
[project_year] => 2014
)

[1] => Array
(
[id] => 8
[project_id] => 4
[company_type] => C1
[capacity_share] => 10
[project_year] => 2014
)

)

)

)

)


I am manipulating above array to create a new following resultant array:
I will create a new array and insert the calculated values in this new array:

Array
(
[0] => Array(
//year_actual of project
'year' => 2016,
//[100+200] : sum of 'project_capacity' where year_actual = 2016
'project_capacity_sum' => 300,
//[12+16] : sum of 'capacity_share' where company_type = C1 and project_year = 2016
'C1_capacity_sum' => 28,
//[14+15] : sum of 'capacity_share' where company_type = C2 and project_year = 2016
'C2_capacity_sum' => 29
)
[1] => Array(
//year_actual of project
'year' => 2014,
//[300+400] : sum of 'project_capacity' where year_actual = 2014
'project_capacity_sum' => 700,
//[20+10] : sum of 'capacity_share' where company_type = C1 and project_year = 2014
'C1_capacity_sum' => 30,
//[22+11] : sum of 'capacity_share' where company_type = C2 and project_year = 2014
'C2_capacity_sum' => 33
)
);


I have succeeded in calculating the field “project_capacity_sum” using the below code:

$projectCapacitySum = array_map(function($data) {
return array_sum(array_column($data, 'project_capacity'));
}, $projects_grouped_by_year);


But I am struggling to calculate other fields for the last two days.

The only useful columns to me are following:

[project_capacity]
and
[year_actual]

Inside "companies" sub array

[company_type]
and
[capacity_share]

Basically I am trying group the array by "year_actual" (which i have already done)
Then find the total "project_capacity" in each year and also total "capacity_share" for each "company_type" in each year. I hope this makes sense.

There is no problem if we use column [project_year] inside the [companies] sub array to achieve the desired output.

I know that I have to do another group by inside the companies sub array..and I am still trying to do so.

I am not concerned about code efficiency or optimization at this point. I am just looking for a working logic.

I am asking for help. Please help me with this.

Thanks.

Answer

To get the needed result extend your initial solution (array_map + array_sum + array_column) with the following approach:

$sumData = array_map(function ($v) {
    $arr = ['year' => current(array_column($v, 'year_actual'))];
    $arr['project_capacity_sum'] = array_sum(array_column($v, "project_capacity"));
    $arr['C2_capacity_sum'] = $arr['C1_capacity_sum'] = 0;

    foreach ($v as $item) {  // iterating through the nested items
        $c_capacities = array_column($item['companies'], 'capacity_share', 'company_type');
        $arr['C1_capacity_sum'] += $c_capacities['C1'];
        $arr['C2_capacity_sum'] += $c_capacities['C2'];
    }

    return $arr;
}, $projects_grouped_by_year);

print_r($sumData);

The output:

Array
(
    [2016] => Array
        (
            [year] => 2016
            [project_capacity_sum] => 300
            [C1_capacity_sum] => 28
            [C2_capacity_sum] => 29
        )

    [2014] => Array
        (
            [year] => 2014
            [project_capacity_sum] => 700
            [C1_capacity_sum] => 30
            [C2_capacity_sum] => 33
        )
)