php array sum key where value is same - php

Question

I have an array that contains a sub-array. I want to sum the values where the key is the same and to make it in one list.
Here is my array:
$array = array( array(x1=> 1, x2 => 3, y5 => 9),
array(x1=> 3, x4 => 1, y5 => 1),
array(x1=> 1, x8 => 5, a5 => 2),
array(x1=> 2, x10 => 3)
);
And I want to have an array like :
$newarray = array(x1=>7 , x2 => 3, x4=>1, x8=>5, x10=> 3, y5=>9, y5=>1, a5=>2));
some try:
foreach($array as $key => $values)
{
foreach($values as $n_k => $n_v)
{
$newarray [$n_k] += $n_v;
}
}

Answer 1

The problem is you are adding a value even if it is not defined.
You can check if not set by and init the value to 0
if ( !isset($newarray[$n_k]) ) $newarray[$n_k] = 0;
Here is the complete code:
$array = array( array('x1'=> 1, 'x2' => 3, 'y5' => 9), array('x1'=> 3, 'x4' => 1, 'y5' => 1), array('x1'=> 1, 'x8' => 5, 'a5' => 2), array('x1'=> 2, 'x10' => 3, 'b5' => 5));
$newarray = array();
foreach($array as $key => $values){
foreach($values as $n_k => $n_v) {
if ( !isset($newarray[$n_k]) ) $newarray[$n_k] = 0;
$newarray[$n_k] += $n_v;
}
}
This will result to:
Array
(
[x1] => 7
[x2] => 3
[y5] => 10
[x4] => 1
[x8] => 5
[a5] => 2
[x10] => 3
[b5] => 5
)

Answer 2

You can first get all the keys from the array and use that in a array_column and array_sum to get your desired output.
This will probably have more benefit if the array is larger.
$array = array( array("x1" => 1, "x2" => 3, "y5" => 9),
array("x1" => 3, "x4" => 1, "y5" => 1),
array("x1" => 1, "x8" => 5, "a5" => 2),
array("x1" => 2, "x10" => 3, "b5" => 5)
);
$keys = [];
// get all keys used in $array
foreach($array as $subarr){
$keys = array_merge($keys, array_keys($subarr));
}
// $keys is now:
// array (0 => 'x1', 1 => 'x2', 2 => 'y5', 3 => 'x1', 4 => 'x4', 5 => 'y5', 6 => 'x1', 7 => 'x8', 8 => 'a5', 9 => 'x1', 10 => 'x10', 11 => 'b5')
// loop only unique keys and sum the values
foreach(array_unique($keys) as $item){
$res[$item] = array_sum(array_column($array, $item));
}
var_dump($res);
https://3v4l.org/WaqlG

Answer 3

That's not my question, but i've found this that can help you:
https://stackoverflow.com/a/14196064/9721446
You have to create a new array, and then for each equal keyid, you're going to add the value. Somethinkg like that i think it works.
if doesn't help you, take a look at this post, that's not mine too!!!!
Associative array, sum values of the same key

Answer 4

<?php
$input = array( array(x1=> 1, x2 => 3, y5 => 9),
array(x1=> 3, x4 => 1, y5 => 1),
array(x1=> 1, x8 => 5, a5 => 2),
array(x1=> 2, x10 => 3)
);
$final = array();
array_walk_recursive($input, function($item, $key) use (&$final){
$final[$key] = isset($final[$key]) ? $item + $final[$key] : $item;
});
print_r($final);
?>