迭代数组计算得分会返回除以零

Question

I have the correct data that I want to use in the view, but I want to slightly change it in the Controller, so it's easier to present in the view.

Each 'question' will always have 6 answers (score). Each score is an integer.

The calculation that I want to perform within each of the question's answers is:

So in the example below, within the answers array of 24 => array:1 [▼:

1. Get the score of index 1, and divided it by the score in index 0.
2. Get the score of index 3, and divided it by the score of index 2.
3. Get the score of index 5, and divided it by the score of index 4.

So at the end of the three iterations, there'll be 3 values within the answer. It will then move on to 25 => array:1 [▶] and perform the same as above.

The slight problem is that the divisor could be 0, which would result in a division by 0 error. I have attempted to mitigate this with an if statement within the loop.

High level array ($groupedQuestionsAudit) overview:

array:7 [▼
  24 => array:1 [▼
    "answers" => array:6 [▼
      0 => ReAudit {#517 ▶}
      1 => ReAudit {#518 ▶}
      2 => ReAudit {#519 ▶}
      3 => ReAudit {#520 ▶}
      4 => ReAudit {#521 ▶}
      5 => ReAudit {#522 ▶}
    ]
  ]
  25 => array:1 [▶]
  26 => array:1 [▶]
  27 => array:1 [▶]
  29 => array:1 [▶]
  30 => array:1 [▶]
  31 => array:1 [▶]
]

Section confirming score variable within array:

array:7 [▼
  24 => array:1 [▼
    "answers" => array:6 [▼
      0 => ReAudit {#517 ▼
        #original: array:9 [▼
          "id" => 337
          "score" => 8
          "created_at" => null
          "updated_at" => null
        ]
      }
      1 => ReAudit {#518 ▶}

Current iteration:

foreach ($groupedQuestionsAudit as $score) {
    foreach ($score as $value) {
        for ($i = 0; $i <= 3; $i++) {
            for ($o = 1; $o <= 4; $o++) {
                if ($value[$o]->score == 0) {
                    $answers['answers'][] = 0;
                } else {
                    $answers['answers'][] = $value[$o]->score / $value[$i]->score;
                }
            }
        }
    }
}

My thought on the above was to loop through each of the questions and use an additional for loop that starts 1 index above the previous one. I can then perform the calculation of index 1's score / index 0's score. I don't think that this works correctly though, as if I temporarily remove the division by 0 check, it returns 112 results (without being in their respective question array) like so:

array:1 [▼
  "answers" => array:112 [▼
    0 => 0
    1 => 1.5
    2 => 1
    3 => 1.5
    4 => 0
    5 => 0
    6 => 0
    7 => 0

The error itself is:

ErrorException in Controller.php line 356: Division by zero which is on the line $answers['answers'][] = $value[$o]->score / $value[$i]->score;

I'm unsure why I'm getting a division by 0, when I'm disregarding the calculation if the divisor is zero.

Many thanks.

Answer 1

It can be simplified a bit. You should only need to nest one loop inside your main loop. You can just add one to get the index of the numerator.

foreach ($groupedQuestionsAudit as $key => $scores) {
    for ($i=0; $i < 6; $i += 2) {
        $divisor = $scores['answers'][$i]->score;
        $numerator = $scores['answers'][$i+1]->score;
        $answers[] = $divisor ? $numerator / $divisor : 0;

        // or $answers[$key][] = $divisor ? $numerator / $divisor : 0;
        // to group the results by the key from $groupedQuestionsAudit

    }
}

I used a ternary for the calculation: $answers[] = $divisor ? $numerator / $divisor : 0;. This is possible because 0 will evaluate to false, and any other number won't.