如何删除$ key和$ value

Question

当我添加htmlspecialchars_decode以阅读法文字母时，它与主代码冲突，并且我无法登录包含该报告的考试标记，它返回同一页>>>有人告诉我（$ key和$ value）是定义了两次，如果正确的话我怎么写代码

function marks($id){

        if(!$this->panelInit->can( "onlineExams.showMarks" )){
            exit;
        }

        $return = array();

        $exam = \online_exams::where('id',$id)->first();
        $return['examDegreeSuccess'] = $exam->examDegreeSuccess;

        $return['grade'] = \DB::table('online_exams_grades')
                    ->where('examId',$id)
                    ->leftJoin('users', 'users.id', '=', 'online_exams_grades.studentId')
                    ->select('online_exams_grades.id as id',
                    'online_exams_grades.examGrade as examGrade',
                    'online_exams_grades.examDate as examDate',
                    'online_exams_grades.examQuestionsAnswers as examQuestionsAnswers',
                    'users.fullName as fullName',
                    'users.id as studentId')
                    ->get();

        foreach ($return['grade'] as $key => $value) {
            $return['grade'][$key]->examQuestionsAnswers = json_decode($return['grade'][$key]->examQuestionsAnswers,true);
            if(is_array($return['grade'][$key]->examQuestionsAnswers)){
                foreach ($return['grade'][$key]->examQuestionsAnswers as $key => $value) {
                    $return['grade'][$key]->examQuestionsAnswers[$key]['title'] = strip_tags(htmlspecialchars_decode( $return['grade'][$key]->examQuestionsAnswers[$key]['title'] ));
                }
            }
            $return['grade'][$key]->examDate = $this->panelInit->unix_to_date($return['grade'][$key]->examDate);
        }

        return json_encode($return);
    }