PHP How to sum values of the array of the same key

Question

This Question might seem duplicate, but I swear to have tried and tried thousands of solutions for many hours now...

I have got an associative multidimentional array like this:

    1 => 
    array (size=1)
      'Pld' => 
        array (size=2)
          'score_good_answers' => string '1' (length=1)
          'score_bad_answers' => string '0' (length=1)
  2 => 
    array (size=1)
      'Aln' => 
        array (size=2)
          'score_good_answers' => string '0' (length=1)
          'score_bad_answers' => string '1' (length=1)
  3=> 
    array (size=1)
      'IPS' => 
        array (size=2)
          'score_good_answers' => string '1' (length=1)
          'score_bad_answers' => string '0' (length=1)
 4 => 
    array (size=1)
      'Pld' => 
        array (size=2)
          'score_good_answers' => string '1' (length=1)
          'score_bad_answers' => string '0' (length=1)
  5 => 
    array (size=1)
      'Aln' => 
        array (size=2)
          'score_good_answers' => string '1' (length=1)
          'score_bad_answers' => string '0' (length=1)
 6 => 
        array (size=1)
          'Aln' => 
            array (size=2)
              'score_good_answers' => string '1' (length=1)
              'score_bad_answers' => string '0' (length=1)

FOR Var_Export :

1=> array ( 'Pld' => array ( 'score_good_answers' => '1', 'score_bad_answers' => '0', ), ), 2 => array ( 'Aln' => array ( 'score_good_answers' => '0', 'score_bad_answers' => '1', ), ), 3 => array ( 'IPS' => array ( 'score_good_answers' => '1', 'score_bad_answers' => '0', ), ), 4 => array ( 'Pld' => array ( 'score_good_answers' => '1', 'score_bad_answers' => '0', ), ),  5 => array ( 'Aln' => array ( 'score_good_answers' => '1', 'score_bad_answers' => '0', ), ),  6 => array ( 'Aln' => array ( 'score_good_answers' => '1', 'score_bad_answers' => '0', ), ),

I need to SUM the all the 'score_good_answers' and the 'score_bad_answers' for all Aln s and Pld s and so forth.

The Worse case scenario is that, this keys ie: are changeable values.

At this level, whatever solution that works will be well appreciated.

I tried the Accepted Answer in this SO Question: How to sum values of the array of the same key?

However, It seems to throw several Errors....

And I Tried Several More Solutions from several SO Questions, ie: How to sum values of the array of the same key? , Array sum of value based on same key , How to sum values via the same key and group by other key and many more...

An other close one was this: How to sum same array in php

And tried:

$array2 = array();
    for($f = 0; $f<count($getCategories); $f++){

        foreach($getCategories[$i] as $k=>$v) {
    if(!isset($array2[$v['Aln']])) {
        $array2[$v['Aln']] = $v;
    } else {
        $array2[$v['Aln']]['score_good_answers'] += $v['score_good_answers'];
    }
}

        }   var_dump($array2);

I still get Several Errors including invalid arguments undefined offsets and many more

Humbly request for any suggestion.

Thank you very much

Answer 1

You can use this code:

$answers = array();

foreach ($getCategories as $categories){

    foreach($categories as $category => $scores){

        foreach ($scores as $type => $score){

            if (isset($answers[$category][$type])){
                $answers[$category][$type] += (int) $score;
            } else {
                $answers[$category][$type] = (int) $score;
            }

        }

    }

}

The output of will be the following array:

Array
(
    [Pld] => Array
        (
            [score_good_answers] => 2
            [score_bad_answers] => 0
        )

    [Aln] => Array
        (
            [score_good_answers] => 2
            [score_bad_answers] => 1
        )

    [IPS] => Array
        (
            [score_good_answers] => 1
            [score_bad_answers] => 0
        )

)

Answer 2

The variable that holds the key is named $f, but you try to use the undefined variable $i on the next line, see? That is one of your warnings and will not do what you want it to. Use $f on the second line.

for($f = 0; $f<count($getCategories); $f++){
    foreach($getCategories[$i] as $k=>$v) {

Your data structure seems a bit odd? Is there always just one key in the second top-most array?

This would be prettier if possible:

array(2) {
  [0] => stdClass#1 (3) {
    public $name => string(4) "Pld"
    public $score_good_answers => int(1)
    public $score_bad_answers=> int(0)
  }
  [1] => stdClass#1 (3) {
    public $name => string(4) "Aln"
    public $score_good_answers => int(0)
    public $score_bad_answers=> int(1)
  }
}

I can not see what end result you want, but give this a try, might not fit what you want though.

$goodAnswersByCategoryDataKey = array();
$badAnswersByCategoryDataKey = array();

foreach ($categories as $i => $category) {
    foreach ($category as $categoryDataKey => $categoryData) {
        if (!isset($goodAnswersByCategoryDataKey[$categoryDataKey])) {
            $goodAnswersByCategoryDataKey[$categoryDataKey] = 0;
        }
        $goodAnswersByCategoryDataKey[categoryDataKey] += $categoryData['score_good_answers'];

        if (!isset($badAnswersByCategoryDataKey[$categoryDataKey])) {
            $badAnswersByCategoryDataKey[$categoryDataKey] = 0;
        }
        $badAnswersByCategoryDataKey[$categoryDataKey] += $categoryData['score_bad_answers'];
    }
}

var_dump(goodAnswersByCategoryDataKey);
var_dump(badAnswersByCategoryDataKey);

Answer 3

If it's an iterative structure like in your example you can do this :

$answers = [];
$nbCat = count($getCategories);
for($i = 0; $i < $nbCat; $i++) {
    foreach($getCategories[$i] as $key => $scores) {
        if(empty($answers[$key])) {
             $answers[$key] = $scores;
        }
        else {
            $answers[$key]['score_good_answers'] += $scores['score_good_answers'];
            $answers[$key]['score_bad_answers'] += $scores['score_bad_answers'];
        }
    }
}