解决Laravel测验结果计算中For循环的索引错位问题

public function calculateResults(){
    $totalCorrect = 0;
    $takenQuestions = request()->input('taken_questions'); // 用户作答的问题ID数组，例如 [1 => "1", 2 => "2", 3 => "3", 4 => "5", 5 => "10"]
    $givenAnswers = request()->input('answer');           // 用户提供的答案数组
    $exam_id = request()->input('exam_id');

    // 获取考试相关问题（此处为Query Builder实例）
    $examQuestions = examQuestion::where('exam_id', $exam_id);

    // 循环遍历用户作答的每道题
    for($i = 1; $i <= count($takenQuestions); $i++){
        // 从数据库中获取当前问题
        $givenQuestion = $examQuestions->find($takenQuestions[$i]);

        if(isset($givenQuestion)){
            // 获取当前问题的正确答案
            $correctAnswer = $givenQuestion->answers->firstWhere('isCorrect', true);

            // 检查用户答案是否与正确答案匹配
            if($correctAnswer->content == $givenAnswers[$i]){ // 潜在的问题点
                $totalCorrect++;
            }
        }
    }
    dd($totalCorrect); // 调试时发现 $totalCorrect 总是为 1
}

Taken Questions:
array:5 [▼
  1 => "1"  // 第1个用户作答的问题，ID为1
  2 => "2"  // 第2个用户作答的问题，ID为2
  3 => "3"  // 第3个用户作答的问题，ID为3
  4 => "5"  // 第4个用户作答的问题，ID为5
  5 => "10" // 第5个用户作答的问题，ID为10
]

if($correctAnswer->content == $givenAnswers[$i]){

if($correctAnswer->content == $givenAnswers[$takenQuestions[$i]]){

public function calculateResults(){
    $totalCorrect = 0;
    $takenQuestions = request()->input('taken_questions');
    $givenAnswers = request()->input('answer');
    $exam_id = request()->input('exam_id');

    $examQuestionsQuery = examQuestion::where('exam_id', $exam_id);

    for($i = 1; $i <= count($takenQuestions); $i++){
        $currentQuestionId = $takenQuestions[$i]; // 获取当前问题的实际ID
        $givenQuestion = $examQuestionsQuery->find($currentQuestionId);

        if(isset($givenQuestion)){
            $correctAnswer = $givenQuestion->answers->firstWhere('isCorrect', true);

            // 使用实际的问题ID作为键来获取用户答案
            // 增加 isset() 检查以防用户未回答某个问题导致 $givenAnswers 中缺少对应键
            if(isset($givenAnswers[$currentQuestionId]) && $correctAnswer->content == $givenAnswers[$currentQuestionId]){
                $totalCorrect++;
            }
        }
    }
    dd($totalCorrect);
}

public function calculateResults(){
    $totalCorrect = 0;
    $takenQuestions = request()->input('taken_questions'); // 假设仍是 [1 => "1", 2 => "2", ...]
    $givenAnswers = request()->input('answer');
    $exam_id = request()->input('exam_id');

    // 预加载所有相关问题及答案，避免N+1查询问题
    // 将 takenQuestions 的值转换为整数数组，以便在 whereIn 查询中使用
    $questionIds = array_values($takenQuestions); 

    $examQuestionsCollection = examQuestion::where('exam_id', $exam_id)
                                            ->whereIn('id', $questionIds) // 只加载用户作答的问题
                                            ->with('answers') // 预加载答案关系
                                            ->get()
                                            ->keyBy('id'); // 将集合按问题ID索引，方便快速查找

    foreach ($questionIds as $questionId) { // 遍历实际的问题ID
        $givenQuestion = $examQuestionsCollection->get($questionId); // 从集合中按ID获取问题

        if ($givenQuestion) { // 检查问题是否存在
            $correctAnswer = $givenQuestion->answers->firstWhere('isCorrect', true);

            // 确保 $correctAnswer 和 $givenAnswers[$questionId] 都存在
            if ($correctAnswer && isset($givenAnswers[$questionId]) && $correctAnswer->content == $givenAnswers[$questionId]) {
                $totalCorrect++;
            }
        }
    }
    dd($totalCorrect);
}

if (isset($givenAnswers[$questionId]) && $correctAnswer->content == $givenAnswers[$questionId]) { ... }

$userAnswer = $givenAnswers[$questionId] ?? null;
if ($correctAnswer && $userAnswer && $correctAnswer->content == $userAnswer) { ... }