Sum all elements in each subarray of a 2d array

Question

I've got the following 2d array and I want to sum all of the elements in each subarray.

Input:

$main_array = [
    [1, 2, 3],
    [2, 4, 5],
    [8, 4, 3]
]

Desired Result:

[6, 11, 15]

I tried the following code:

foreach ($main_array as $key => $value)
    $main_array[$key] = Array('1' => array_sum($value));
print_r($main_array);

But the array structure I got was:

Array 
( 
    [0] => Array 
    ( 
        [1] => 6 
    ) 
    [1] => Array 
    ( 
        [1] => 11
    ) 
    [2] => Array 
    ( 
        [1] => 15 
    ) 
)

Muhammad Hasan Khan · Accepted Answer · 2011-10-16 04:58:16Z

6

When you're calling Array function you're explicitly making an array so you have to remove this from Array('1'=>array_sum($value));

This is how your code should look like

foreach ($main_array as $key => $value)
  $main_array[$key] = array_sum($value);

answered Oct 16, 2011 at 4:58

Muhammad Hasan Khan

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Comments

Vincent Ramdhanie · Accepted Answer · 2011-10-16 05:00:19Z

2

Try this:

  foreach ($main_array as $key => $value)
     $main_array[$key] = array_sum($value);

That is, place the sum directly in the top level array.

answered Oct 16, 2011 at 5:00

Vincent Ramdhanie

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Comments

mickmackusa · Accepted Answer · 2021-06-27 03:03:01Z

1

Call array_sum() on every row in your input array. array_map() makes this operation expressive, concise, and doesn't require any new variables to be declared.

Code: (Demo)

$array = [
    [1, 2, 3],
    [2, 4, 5],
    [8, 4, 3],
];

var_export(array_map('array_sum', $array));

Output:

array (
  0 => 6,
  1 => 11,
  2 => 15,
)

answered Jun 27, 2021 at 3:03

mickmackusa♦

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