Как реструктурировать массив так, чтобы ключ вложенного массива стал ключом массива

Question

Первое размещение здесь и действительно нужна помощь. Относительно новый для php У меня есть массив, который я хотел бы перестроить. У меня есть предметы на высшем уровне со студентами в подгруппе. Я хотел бы изменить структуру так, чтобы студенты были на верхнем уровне с предметами в подмассиве.

$startingArray = [
    [   "subject" => "Physics",
        "student" => [
            ["id" => "00003", "Name" => "Peter", "email" => "peter@schooool.com",],
            ["id" => "00004", "Name" => "Mary", "email" => "mary@schooool.com",],
            ["id" => "00005", "Name" => "Jane", "email" => "jane@schooool.com",],
        ]
    ],
    [   "subject" => "Chemistry",
        "student" => [
            ["id" => "00003", "Name" => "Peter", "email" => "peter@schooool.com",],
            ["id" => "00004", "Name" => "Mary", "email" => "mary@schooool.com",],
            ["id" => "00005", "Name" => "Jane", "email" => "jane@schooool.com",],
        ]
    ],
    [   "subject" => "Mathematics",
        "student" => [
            ["id" => "00003", "Name" => "Peter", "email" => "peter@schooool.com",],
            ["id" => "00006", "Name" => "Fred", "email" => "fred@schooool.com",],
            ["id" => "00007", "Name" => "Wilma", "email" => "wilma@schooool.com",],
        ]
    ],
    [   "subject" => "Biology",
        "student" => [
            ["id" => "00004", "Name" => "Mary", "email" => "mary@schooool.com",],
            ["id" => "00006", "Name" => "Fred", "email" => "fred@schooool.com",],
            ["id" => "00008", "Name" => "Alison", "email" => "alison@schooool.com",],
        ]
    ]
];

Я хочу, чтобы мой новый массив был таким;

$endingArray = [
     "students" => [
         [   "id" => "00003",
             "Name" => "Peter",
             "email" => "peter@schooool.com",
             "subjects" => [ "Physics", "Chemistry", "Mathematics", ],
         ],
         [   "id" => "00004",
             "Name" => "Mary",
             "email" => "mary@schooool.com",
             "subjects" => [ "Physics", "Chemistry", "Biology", ],
         ],
         [   "id" => "00005",
             "Name" => "Jane",
             "email" => "jane@schooool.com",
             "subjects" => [ "Physics", "Chemistry", ],
         ],
         [   "id" => "00006",
             "Name" => "Fred",
             "email" => "fred@schooool.com",
             "subjects" => [ "Mathematics", "Biology", ],
         ],
         [   "id" => "00007",
             "Name" => "Wilma",
             "email" => "wilma@schooool.com",
             "subjects" => [ "Mathematics", "Biology", ],
         ],
         [   "id" => "00008",
             "Name" => "Alison",
             "email" => "alison@schooool.com",
             "subjects" => [ "Physics", "Biology", ],
         ],
     ],
];

Iпробую 2 этапа процесса. Во-первых, создать новый массив студентов без предметов. Это прекрасно работает.

Затем я пытаюсь добавить предметы, но я знаю, что моя логика неверна, и код, который я имею, просто создает новую строку для каждого студента и каждого предмета.

foreach ( $startingArray as $row ) {
    $students = $row['student'];
    foreach ($students as $student) {
        if (!in_array($student, $studentsArray)) {
            $studentsArray[] = $student;
        }
    }
}

второй шаг просто производит мусор

    $s1 = $student['id'];
    foreach ($startingArray as $row) {
        $subject = $row['subject'];
        $students = $row['student'];
        foreach ($students as $s2) {
            if ($s2['id]'] = $s1) {
                $student['subjects'] = $subject;
                array_push($studentsArray, $student);
            }
        }
    }
}

Любая помощь приветствуется!

Answer 1

Вот что вы можете сделать:

$newArray = [];
foreach ($startingArray as $item) {
    foreach ($item['student'] as $student) {
        if (empty($newArray[$student['id']])) {
            $student['subjects'] = [];
            $newArray[$student['id']] = $student;
        }

        $newArray[$student['id']]['subjects'][] = $item['subject'];
    }
}

Образец скрипки здесь .

Answer 2

Если вам нужно сохранить последовательный идентификатор, как в вашем примере, сделайте это

$newArray = [];
foreach ($startingArray as $item) {
    foreach ($item["student"] as $student) {
        $filter = array_filter($newArray, function ($d) use ($student) {
            return ($d["id"] == $student["id"]);
        });
        if (!$filter) {
            $student["subjects"][] = $item['subject'];
            $newArray[] = $student;
        } else {
            $newArray[key($filter)]["subjects"][] = $item["subject"];
        }
    }
}

$finalArray = [
    'students' => $newArray
];

Окончательный результат будет

Array
(
    [students] => Array
        (
            [0] => Array
                (
                    [id] => 00003
                    [Name] => Peter
                    [email] => peter@schooool.com
                    [subjects] => Array
                        (
                            [0] => Physics
                            [1] => Chemistry
                            [2] => Mathematics
                        )

                )

            [1] => Array
                (
                    [id] => 00004
                    [Name] => Mary
                    [email] => mary@schooool.com
                    [subjects] => Array
                        (
                            [0] => Physics
                            [1] => Chemistry
                            [2] => Biology
                        )

                )

            [2] => Array
                (
                    [id] => 00005
                    [Name] => Jane
                    [email] => jane@schooool.com
                    [subjects] => Array
                        (
                            [0] => Physics
                            [1] => Chemistry
                        )

                )

            [3] => Array
                (
                    [id] => 00006
                    [Name] => Fred
                    [email] => fred@schooool.com
                    [subjects] => Array
                        (
                            [0] => Mathematics
                            [1] => Biology
                        )

                )

            [4] => Array
                (
                    [id] => 00007
                    [Name] => Wilma
                    [email] => wilma@schooool.com
                    [subjects] => Array
                        (
                            [0] => Mathematics
                        )

                )

            [5] => Array
                (
                    [id] => 00008
                    [Name] => Alison
                    [email] => alison@schooool.com
                    [subjects] => Array
                        (
                            [0] => Biology
                        )

                )

        )

)