SUM values across two multidimensional arrays in PHP - php

Question

I have a problem how to SUM values of two multidimensional arrays in PHP.
Two arrays are storred in variables for example $array_1 and $array_2
Both $array_1 and $array_2 have sub-arrays, which again have data stored in their respective arrays. Notice that data is organized as x-data and y-data, where y-data is just a DATE stamp.
I need to SUM x-data values of these two arrays $array_1 and $array_2, with respect to y-data (DATE) dimension. This is why it got tricky for me, the closes answers I have found have only numbers.
Example:
$array_1
Array
(
[0] => object
(
[x-data] => Array
(
[data1] => 0
[data2] => 1
[data3] => 2
[data4] => 3
[data5] => 4
[data6] => 5
[data7] => 6
[data8] => 7
)
[y-data] => Array
(
[date] => 20141127
)
)
[1] => object
(
[x-data] => Array
(
[data1] => 2
[data2] => 4
[data3] => 6
[data4] => 8
[data5] => 10
[data6] => 12
[data7] => 14
[data8] => 16
)
[y-data] => Array
(
[date] => 20141128
)
)
)
$array_2
Array
(
[0] => object
(
[x-data] => Array
(
[data1] => 0
[data2] => 1
[data3] => 2
[data4] => 3
[data5] => 4
[data6] => 5
[data7] => 6
[data8] => 7
)
[y-data] => Array
(
[date] => 20141127
)
)
[1] => object
(
[x-data] => Array
(
[data1] => 0
[data2] => 1
[data3] => 2
[data4] => 3
[data5] => 4
[data6] => 5
[data7] => 6
[data8] => 7
)
[y-data] => Array
(
[date] => 20141128
)
)
)
$result = $array_1 + $array_2 should look like this:
Array
(
[0] => object
(
[x-data] => Array
(
[data1] => 0
[data2] => 2
[data3] => 4
[data4] => 6
[data5] => 8
[data6] => 10
[data7] => 12
[data8] => 14
)
[y-data] => Array
(
[date] => 20141127
)
)
[1] => object
(
[x-data] => Array
(
[data1] => 2
[data2] => 5
[data3] => 8
[data4] => 11
[data5] => 14
[data6] => 17
[data7] => 20
[data8] => 23
)
[y-data] => Array
(
[date] => 20141128
)
)
)
I have tried some things, like foreach() inside foreach() but I got a multiplication effect of the array values (2 x 2 = 4 subarrays instead of 2).
Any help?
Thanks!

Answer 1

Here's a partial answer as this should only only work if $array1 and $array2 have same number of elements and have unique y-datas, and each of their x-data (with y-data in common) have the same number of elements.
$result = array_multisum($array1, $array2);
function array_multisum($array1, $array2)
{
$newArray = array();
foreach ($array1 as $object1) {
$newObject = new stdClass();
// find object in the 2nd array having the same data as current object
foreach ($array2 as $object2) {
// if object is found, sum the x-data with the current object
if ($object1->{'y-data'}['date'] === $object2->{'y-data'}['date']) {
$newObject->{'x-data'} = data_sum($object1->{'x-data'}, $object2->{'x-data'});
break;
}
}
$newObject->{'y-data'} = $object1->{'y-data'};
$newArray[] = $newObject;
}
return $newArray;
}
function data_sum($data1, $data2)
{
$newData = array();
// sum up the values for each key
foreach (array_keys($data1) as $key) {
$newData[$key] = $data1[$key] + $data2[$key];
}
return $newData;
}