Sum array values of a column within each column of an array with 3 levels

Question

I'm trying to use array_sum() on columns within columns of a multidimensional array.

For eg: I have an array that looks like this:

$array = [
    [['value' => 1100], ['value' => 1000], ['value' => 3000]],
    [['value' => 1200], ['value' => 2000], ['value' => 2000]],
    [['value' => 1300], ['value' => 4000], ['value' => 1000]],
];

I tried with:

$arr = [];
foreach($array as $point){
   $arr[] = array_sum(array_column($array, $point[0]['value']));
}
print_r($arr);

but I'm expecting this output:

[['value' => 3600], ['value' => 7000], ['value' => 6000]]

Or more simply: [3600, 7000, 6000]

Tested here: https://onecompiler.com/php/3y3mxqky9

Answer 1

You can sum your columns doing like this:

foreach($array as $key => $point){
  $arr[] = array_sum(array_column( array_column($array,$key),'value'));
}
print_r($arr);

Answer 2

Since you wish to have the sum vertically and not horizontally, the array_column style you used won't work. You can simply achieve this with 2 nested loops like below:

<?php

$arr = [];
foreach($array as $point){
   foreach($point as $k => $v){
      $arr[$k] = ($arr[$k] ?? 0) + $v['value'];
   }
}
print_r($arr); 

Online Demo

Answer 3

Transpose your input array, then isolate and sum the value column of data.

The variadic offering of $array to array_map() is the transposing part.

In other words, array_map(fn(...$col) => $col, ...$array) converts rows of data into columns of data.

Code: (Demo)

var_export(
    array_map(
        fn(...$col) => array_sum(array_column($col, 'value')),
        ...$array
    )
);

Output:

array (
  0 => 3600,
  1 => 7000,
  2 => 6000,
)