Конвертировать массив PHP в дерево JSON

Question

У меня есть массив в этом формате:

array(
    array('id' => 1, 'parent_id' => null, 'name' => 'lorem ipsum'),
    array('id' => 2, 'parent_id' => 1, 'name' => 'lorem ipsum1'),
    array('id' => 3, 'parent_id' => 1, 'name' => 'lorem ipsum2'),
    array('id' => 4, 'parent_id' => 2, 'name' => 'lorem ipsum3'),
    array('id' => 5, 'parent_id' => 3, 'name' => 'lorem ipsum4'),
    array('id' => 6, 'parent_id' => null, 'name' => 'lorem ipsum5'),
);

Мне нужно преобразовать этот массив в объект json с этим стилем:

var json = {  
    id: "1",  
    name: "loreim ipsum",  
    data: {},  
    children: [{  
        id: "2",  
        name: "lorem ipsum1",  
        data: {},  
        children: [{  
            id: "3",  
            name: "lorem ipsum2",  
            data: {},  
            children: [{
            ..............

Как я могу это сделать? Спасибо.

Answer 1

Мое решение:

$data = array(
    array('id' => 1, 'parent_id' => null, 'name' => 'lorem ipsum'),
    array('id' => 2, 'parent_id' => 1, 'name' => 'lorem ipsum1'),
    array('id' => 3, 'parent_id' => 1, 'name' => 'lorem ipsum2'),
    array('id' => 4, 'parent_id' => 2, 'name' => 'lorem ipsum3'),
    array('id' => 5, 'parent_id' => 3, 'name' => 'lorem ipsum4'),
    array('id' => 6, 'parent_id' => null, 'name' => 'lorem ipsum5'),
);

$itemsByReference = array();

// Build array of item references:
foreach($data as $key => &$item) {
   $itemsByReference[$item['id']] = &$item;
   // Children array:
   $itemsByReference[$item['id']]['children'] = array();
   // Empty data class (so that json_encode adds "data: {}" ) 
   $itemsByReference[$item['id']]['data'] = new StdClass();
}

// Set items as children of the relevant parent item.
foreach($data as $key => &$item)
   if($item['parent_id'] && isset($itemsByReference[$item['parent_id']]))
      $itemsByReference [$item['parent_id']]['children'][] = &$item;

// Remove items that were added to parents elsewhere:
foreach($data as $key => &$item) {
   if($item['parent_id'] && isset($itemsByReference[$item['parent_id']]))
      unset($data[$key]);
}

// Encode:
$json = json_encode($data);

Answer 2

Вот код, чтобы сделать то, что вам нужно. не требуется элементы в родительском-дочернем порядке в массиве, но будет быстрее, если они.

Пожалуйста, изучите комментарии, чтобы понять, что делает код и почему; и если у вас все еще есть вопросы, задавайте их тоже!

// Assume your array is $data

$root = new stdClass; // this is your root item
$objectMap = array(); // this holds objects indexed by their id

// Since we need to iterate over the array, but there may be no guarantee
// that an item's parent will be always encountered before the item itself,
// we loop as many times as needed, skipping items whose parent we have not
// yet seen. Hopefully we will see it later and be able to process these
// items in the next iteration.
while (!empty($data)) {

    // Remember how many items there are when starting the loop
    $count = count($data);

    // Do the actual work!
    foreach ($data as $key => $row) {
        $parentId = $row['parent_id'];

        if ($parentId === null) {
            // We just met the root element
            $current = $root;
        }
        else if (isset($objectMap[$parentId])) {
            // We met an element with a parent that we have already seen
            $current = new stdClass;
        }
        else {
            // We met an element with an unknown parent; ignore it for now
            continue;
        }

        // Put the current element on the map so that its children will
        // be able to find it when we meet them
        $objectMap[$row['id']] = $current;

        // Add the item to its parent's children array
        $objectMap[$parentId]->children[] = $current;

        // Set the item's properties
        $current->id = $row['id'];
        $current->name = $row['name'];
        $current->data = new stdClass; // always empty
        $current->children = array();

        // We successfully processed this, remove it (see why below!)
        unset($data[$key]);
    }

    // OK, we looped over the array once. If the number of items has
    // not been reduced at all, it means that the array contains only
    // items whose parents do not exist. Instead of looping forever,
    // let's just take what we are given and stop here.
    if ($count == count($data)) {
        break;
    }

    // If there are still items in $data, we will now iterate again
    // in the hope of being able to process them in the next iteration
}

// All set! If $data is not empty now, it means there were items
// with invalid parent_ids to begin with.
$output = json_encode($root);

Answer 3

Мой дубль (я знаю, что ответ принят, но я работал над этим, поэтому я опубликую id = P)

<code>// Test data
$data = array(
    array('id' => 1, 'parent_id' => null, 'name' => 'lorem ipsum'),
    array('id' => 2, 'parent_id' => 1, 'name' => 'lorem ipsum1'),
    array('id' => 3, 'parent_id' => 1, 'name' => 'lorem ipsum2'),
    array('id' => 4, 'parent_id' => 2, 'name' => 'lorem ipsum3'),
    array('id' => 5, 'parent_id' => 3, 'name' => 'lorem ipsum4'),
    array('id' => 6, 'parent_id' => null, 'name' => 'lorem ipsum5'),
);

// Randomize, because the data may not be in a top-down order
shuffle( $data );

// Parse and inspect the result
$builder = new TreeBuilder( $data );
echo '<pre>', print_r( $builder->getTree() ), '

';class TreeBuilder {protected $ leafIndex = array ();защищенный $ tree = array ();защищенный стек $;function __construct ($ data) {$ this-> stack = $ data;while (count ($ this-> stack)) {$ this-> branchify (array_shift ($ this-> stack));}} защищенная функция branchify (& $ leaf) {// лист корневого уровня?if (null === $ leaf ['parent_id']) {$ this-> addLeaf ($ this-> tree, $ leaf);} // Мы уже нашли родителя этого листа?иначе if (isset ($ this-> leafIndex [$ leaf ['parent_id']])) {$ this-> addLeaf ($ this-> leafIndex [$ leaf ['parent_id']] ['children'], $ leaf);} else {// Нет, поместите его обратно в стек $ this-> stack [] = $ leaf;}} защищенная функция addLeaf (& $ branch, $ leaf) {// Добавить лист в ветку $ branch [] = array ('id' => $ leaf ['id'], 'name' => $ leaf ['name'], 'data' => new stdClass, 'children' => array ());// Сохраняем ссылку, чтобы мы могли выполнить поиск O (1) позже $ this-> leafIndex [$ leaf ['id']] = & $ branch [count ($ branch) -1];} защищенная функция addChild ($ branch, $ leaf) {$ this-> leafIndex [$ leaf ['id']] & = $ branch ['children'] [] = $ leaf;} public function getTree () {return $ this-> tree;}}