PHP将对象转换为数组的数组

我有3个表，在连接名称并输出角色后

$encoded = array();
while($res = mysqli_fetch_assoc($result)) {
    echo json_encode($res);
}

我知道了

{"student_id":"1","student_name":"john","score_id":"1","score_type":"E","score_name":"England"}
{"student_id":"1","student_name":"john","score_id":"2","score_type":"B","score_name":"Brazil"}

现在我正努力将它们转换成我想要的格式，客户端站点必须有这样的格式

//json
[{
"student_id":"1",
"student_name":"john",
"scores": [{
        "score_id":"1",
        "score_type":"E",
        "score_name":"England"
    },{
        "score_id":"2",
        "score_type":"B",
        "score_name":"Brazil"
    }]
}]

---

挑战在于它与同一个人有重复的行。

使用数组

$encoded

处理输出，一旦生成，就可以使用JSON打印它

在此解决方案中，数组将按

学生id

索引，分数按

分数id

索引。对于学生，这是必须的，对于分数，建议：

$encoded = array();
while($res = mysqli_fetch_assoc($result)) {
  // Student's details
  $encoded[$res['student_id']] = array(
      'student_id' => $res['student_id'],
      'student_name' => $res['student_name'],
  );
  // Student's score details
  $encoded[$res['student_id']]['scores'][$res['score_id']] = array(
      'score_id' => $res['score_id'],
      'score_type' => $res['score_type'],
      'score_name' => $res['score_name'],
  );
}
echo json_encode($encoded);

---

注意：这是一般性的回答，因为我不知道$res中数据的确切结构。

请查找下面的代码以获得问题中提到的json格式

$students = [];
$sampleData    = [
          [

              "student_id"=>"1",
              "student_name"=>"john",
              "score_id"=>"1",
              "score_type"=>"E",
              "score_name"=>"England",
          ],
          [
              "student_id"=>"1",
              "student_name"=>"john",
              "score_id"=>"2",
              "score_type"=>"B",
              "score_name"=>"Brazil",
          ],
];
foreach ($sampleData as $res) {

    //if student not found by id then continue
    if (empty($res['student_id'])) {
        continue;
    }

    $student = [];
    //get the already exists student to add scores
    if(!empty($students[$res['student_id']])) {
       $student = $students[$res['student_id']];
    }


    //prepare the student array
    $student['student_id']             = $res['student_id'];
    $student['student_name']           = $res['student_name'];
    $student['scores'][]['score_id']   = $res['score_id'];
    $student['scores'][]['score_type'] = $res['score_type'];
    $student['scores'][]['score_name'] = $res['score_name'];

    $students[$res['student_id']] = $student;
}

echo json_encode(array_values($students));

希望这有帮助

---

您可以发现工作示例

听起来像是您应该调整查询以删除已编码或解码的json的重复。可以是object或assoc。你知道Doctrine2 ORM吗？使用子属性定义模型（对象）并将其映射到数据库表。条令获取行并构建对象。。。在您的例子中，可能是一个带有分数子对象的学生模型。在某些情况下，由于性能原因，您不使用ORM。。。但是它使处理复杂的数据结构变得更加容易。可以避免这一行吗<代码>$arr=$students[$res['contact_id']]？？[];我还没有使用php 7。您的答案不起作用，我尝试了，我给了我2个数组。很抱歉，出现意外错误，请稍后再试或与JDoodle支持部门联系。@globin虽然我已更新了代码，以反映您发布的更新。