Online PHP editor | output for bhF3k

@ 2018-06-13T16:51:37Z

<?php
$items = [
    [
        "user_id" => "User 1",
        "question_1" => "Question 1?",
        "question_2" => "Question 2?"
    ],
    [
        "user_id" => "User 2",
        "question_1" => "Question 2?",
        "question_2" => "Question 3?"
    ],
    [
        "user_id" => "User 3",
        "question_1" => "Question 3?",
        "question_2" => "Question 1?"
    ],
    [
        "user_id" => "User 4",
        "question_1" => "Question 1?",
        "question_2" => "Question 2?"
    ],
    [
        "user_id" => "User 5",
        "question_1" => "Question 2?",
        "question_2" => "Question 3?"
    ],
    [
        "user_id" => "User 1",
        "question_1" => "Question 4?",
        "question_2" => "Question 5?"
    ],
    [
        "user_id" => "User 2",
        "question_1" => "Question 5?",
        "question_2" => "Question 6?"
    ],
    [
        "user_id" => "User 3",
        "question_1" => "Question 6?",
        "question_2" => "Question 4?"
    ],
    [
        "user_id" => "User 4",
        "question_1" => "Question 4?",
        "question_2" => "Question 5?"
    ],
    [
        "user_id" => "User 5",
        "question_1" => "Question 5?",
        "question_2" => "Question 6?"
    ],
    [
        "user_id" => "User 1",
        "question_1" => "Question 7?",
        "question_2" => "Question 8?"
    ]
];

$result = [];

foreach ($items as $item) {
    $userId = $item['user_id'];
    unset($item['user_id']);
    if (!array_key_exists($userId, $result)) {
        $result[$userId] = [
            'user_id' => $userId,
            'questions' => array_values($item)
        ];
        continue;
    }
    $result[$userId]['questions'] = array_merge(
        array_values($result[$userId]['questions']),
        array_values($item)
    );
}

$result = array_values(array_map(function($y) {
    $y['questions'] = array_unique($y['questions']);
    return $y;
}, $result));

print_r($result);

Output for 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.4, 8.3.6 - 8.3.7: Array ( [0] => Array ( [user_id] => User 1 [questions] => Array ( [0] => Question 1? [1] => Question 2? [2] => Question 4? [3] => Question 5? [4] => Question 7? [5] => Question 8? ) ) [1] => Array ( [user_id] => User 2 [questions] => Array ( [0] => Question 2? [1] => Question 3? [2] => Question 5? [3] => Question 6? ) ) [2] => Array ( [user_id] => User 3 [questions] => Array ( [0] => Question 3? [1] => Question 1? [2] => Question 6? [3] => Question 4? ) ) [3] => Array ( [user_id] => User 4 [questions] => Array ( [0] => Question 1? [1] => Question 2? [2] => Question 4? [3] => Question 5? ) ) [4] => Array ( [user_id] => User 5 [questions] => Array ( [0] => Question 2? [1] => Question 3? [2] => Question 5? [3] => Question 6? ) ) )
Output for 8.3.5: Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0 Array ( [0] => Array ( [user_id] => User 1 [questions] => Array ( [0] => Question 1? [1] => Question 2? [2] => Question 4? [3] => Question 5? [4] => Question 7? [5] => Question 8? ) ) [1] => Array ( [user_id] => User 2 [questions] => Array ( [0] => Question 2? [1] => Question 3? [2] => Question 5? [3] => Question 6? ) ) [2] => Array ( [user_id] => User 3 [questions] => Array ( [0] => Question 3? [1] => Question 1? [2] => Question 6? [3] => Question 4? ) ) [3] => Array ( [user_id] => User 4 [questions] => Array ( [0] => Question 1? [1] => Question 2? [2] => Question 4? [3] => Question 5? ) ) [4] => Array ( [user_id] => User 5 [questions] => Array ( [0] => Question 2? [1] => Question 3? [2] => Question 5? [3] => Question 6? ) ) )

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