在PHP中将2D数组转换为JSON

My goal is to make a single database hit to generate a JSON array of objects with attributes that could be also be an array of objects, which could also have attributes that array of objects etc of an arbitrary (but known) depth.

我的目标是使单个数据库命中以生成具有属性的JSON对象数组,这些属性也可以是对象数组,其也可以具有任意(但已知)深度的对象数组等属性。

I get a 2D array from my database using a PDO object.

我使用PDO对象从我的数据库中获取2D数组。

$stmt = $this->pdo->prepare($sql);
$stmt->execute($args);
$TwoDimArray = $stmt->fetchAll(PDO::FETCH_ASSOC);
return $TwoDimArray;

So in my example, I have a Quiz, that can have questions, that can have answers. So a depth of 3. So assuming I have a 2D Array such as the table below, how would I make this JSON array using that data. (Note: other data has been removed for clarity sake, but questions and answers could have other attributes.)

所以在我的例子中,我有一个测验,可以有问题,可以有答案。所以深度为3.所以假设我有一个2D数组,如下表,我将如何使用该数据制作这个JSON数组。 (注意:为清楚起见,已删除其他数据,但问题和答案可能具有其他属性。)

Edit: This is my attempt. It is horribly inefficient and not very abstract for the general case but this code will achieve the right answer for small data sets.

编辑:这是我的尝试。对于一般情况来说,这是非常低效的并且不是很抽象,但是这个代码将为小数据集获得正确的答案。

$data = ($database -> query($sql,$args)); // the result is $TwoDimArray
$quizes = array();
$quiz_id_list = array();
foreach($data as $quizkey => $quizvalue){
    if(!in_array($quizvalue["quiz_id"], $quiz_id_list)) {
        array_push($quiz_id_list, $quizvalue["quiz_id"]);
        $question_id_list = array();
        $questions = array();
        foreach ($data as $questionskey => $questionsvalue) {
            if ($quizvalue["quiz_id"] == $questionsvalue["quiz_id"] && !in_array($questionsvalue["question_id"], $question_id_list)) {
                $answers = array();
                array_push($question_id_list, $questionsvalue["question_id"]);
                foreach ($data as $answerskey => $answersvalue) {
                    $myanswer = array();
                    if ($questionsvalue["question_id"] == $answersvalue["question_id"]) {
                        $myanswer["answer_id"] = $answersvalue["answer_id"];
                        array_push($answers, $myanswer);

                    }
                }
                $myquestion = array();
                $myquestion["question_id"] = $questionsvalue["question_id"];
                $myquestion["answers"] = $answers;
                array_push($questions, $myquestion);

            }
        }
        $myquiz = array();
        $myquiz["quiz_id"] = $quizvalue["quiz_id"];
        $myquiz["questions"] = $questions;
        array_push($quizes, $myquiz);
    }

}
return json_encode($quizes);

The contents of $data looks like this:

$ data的内容如下所示:

array (
  0 =>array('quiz_id' => '1',   'question_id' => '1', 'answer_id' => '1',),
  1 =>array('quiz_id' => '1',   'question_id' => '1', 'answer_id' => '2',),
  ...
  5 =>array('quiz_id' => '1', 'question_id' => '2', 'answer_id' => '6',),
  6 =>array('quiz_id' => '1', 'question_id' => '2', 'answer_id' => '7',),
  ...
  22 =>array('quiz_id' => '2', 'question_id' => '6', 'answer_id' => '23',),
  23 =>array('quiz_id' => '2', 'question_id' => '6', 'answer_id' => '24',),
)

The result should return a json object that looks like this:

结果应该返回一个如下所示的json对象:

[
    {
        "quiz_id": 1,
        "questions": [
            {"question_id":1, "answers": [{"answer_id":1}, {"answer_id":2}, {"answer_id":3},{"answer_id":4}]}, 
            {"question_id":2, "answers": [{"answer_id":5}, {"answer_id":6}, {"answer_id":7},{"answer_id":8}]}, 
            {"question_id":3, "answers": [{"answer_id":9}, {"answer_id":10}, {"answer_id":11},{"answer_id":12}]}
        ]
    },
    {
        "quiz_id": 2,
        "questions": [
            {"question_id":4, "answers": [{"answer_id":13}, {"answer_id":14}, {"answer_id":15},{"answer_id":16}]}, 
            {"question_id":5, "answers": [{"answer_id":17}, {"answer_id":18}, {"answer_id":19},{"answer_id":20}]}, 
            {"question_id":6, "answers": [{"answer_id":21}, {"answer_id":22}, {"answer_id":23},{"answer_id":24}]}
        ]
    }
]

1 个解决方案

#1

You say this is the contents of $TwoDimArray There is not much that can be done with it. I suspect there is something missing yet.

你说这是$ TwoDimArray的内容用它做的事情并不多。我怀疑还有一些东西丢失了。

array ( 'quiz_id' => '1', 'question_id' => '1', 'answer_id' => '1', ), 
array ( 'quiz_id' => '1', 'question_id' => '1', 'answer_id' => '2', ), 
array ( 'quiz_id' => '1', 'question_id' => '1', 'answer_id' => '3', ),

This will get rid of your "redundant data":

这将摆脱你的“冗余数据”:

foreach($TwoDimArray as $value){
  $quiz[$value['quiz_id']][$value['question_id']][$value['question_id']] =  1;
}