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

Question

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

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.

how are you using the other columns exactly? Give us a code example of what is in fact not working, it is hard to figure this out ourselves. — Tikkes
– Tikkes, Commented Jun 26, 2016 at 12:11
The only useful columns to me are following: For each project inside each year: [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. — Neelkanth Kaushik
– Neelkanth Kaushik, Commented Jun 26, 2016 at 12:22
There is no problem if we use column [project_year] inside the [companies] sub array to achieve the desired output. — Neelkanth Kaushik
– Neelkanth Kaushik, Commented Jun 26, 2016 at 12:28
One more question comes to mind right now though, how are you addressing these company types and shared capacity? Remember that you are in a multidimensional array and will have to do a second "Map" in order to process this. array.map(function(data){ ... $returnvalue = array.map($secondArrayData) {...}, $data.companies ...}, $projects_by_year);. — Tikkes
– Tikkes, Commented Jun 26, 2016 at 12:28
I know that I have to do another group by inside the companies sub array..and I am still trying to do so. — Neelkanth Kaushik
– Neelkanth Kaushik, Commented Jun 26, 2016 at 12:32

RomanPerekhrest · Accepted Answer · 2016-06-26 15:48:24Z

1

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
        )
)

edited Jun 26, 2016 at 15:48

answered Jun 26, 2016 at 15:31

RomanPerekhrest

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1 Comment

Neelkanth Kaushik Over a year ago

Hi, @RomanPerekhrest. I played with your code and tried to extend it to next level. I succeeded to some extent, but then i found two issues and I am working on that. I posting a new question here. It would be great if you have a look at it as per your convenience. Thanks.

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