php - 节点链接树和数据由 PHP 在 json 文件中填充

Question

我使用这里的嵌套集模型:http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/以及来自 Depth of a Sub-Tree 部分的查询。

我想使用这张图 http://bl.ocks.org/mbostock/4339184使用我数据库中的数据，但我不知道如何在 PHP 中设计算法来编写 json 数据。flare.json 在这里 http://bl.ocks.org/mbostock/raw/4063550/flare.json (我没有使用 size 属性)

我写了一些代码，但我迷路了，我不知道该怎么做:

$subtree = array(
  ['name' => 'ELECTRONICS',             'depth' => 0],
  ['name' =>    'TELEVISIONS',          'depth' => 1],
  ['name' =>        'TUBE',             'depth' => 2],
  ['name' =>        'LCD',              'depth' => 2],
  ['name' =>        'PLASMA',           'depth' => 2],
  ['name' =>    'PORTABLE ELECTRONICS', 'depth' => 1],
  ['name' =>        'MP3 PLAYERS',      'depth' => 2],
  ['name' =>            'FLASH',        'depth' => 3],
  ['name' =>        'CD PLAYERS',       'depth' => 2],
  ['name' =>        '2 WAY RADIOS',     'depth' => 2],
);

function buildTree($data) {
    $tree    = [];
    $current = 0;

    foreach ($data as $key => $child) {
        // Root
        if ($key == $current) {
            $tree['name'] = $child['name'];
            $lastLevel    = $child['depth'];
        // Child
        } elseif( && $child['depth'] == ($lastLevel + 1)) {
            if (!isset($tree['children'])) {
                $tree['children'] = [];
            }
            $tree['children'][] = buildTree(array_slice($data, $key));
            $current++;
        }
    }

    return $tree;
}

$tree = buildTree($subtree);

print_r($tree);

非常感谢您的帮助!

Answer 1

您需要能够在到达“非子级”时通过返回到目前为止的结果来停止递归循环。此外，您不需要 $current，因为在每个递归循环中，您的数组都被切片并且第一个 $key 始终为 0:

function buildTree($data) {

    $tree    = array();

    foreach ($data as $key => $child) {
        // Root
        if ($key == 0){
            $tree['name'] = $child['name'];
            $lastLevel    = $child['depth'];
        // Child
        } else if(($child['depth'] == ($lastLevel + 1))) {
            if (!isset($tree['children'])) {
                $tree['children'] = array();
            }
            $tree['children'][] = buildTree(array_slice($data,$key));
        }
        else if($child['depth'] <= ($lastLevel)){
            return $tree;
        }
    }
    return $tree;
}

$tree = buildTree($subtree);

print_r($tree);