将平面数组转换为特定数组格式

Question

各位 PHP 程序员，请考虑以下 DB 结果：

+---------+-----------+---------------+--------+
| node_id | parent_id | path          | branch |
+---------+-----------+---------------+--------+
|       1 |         0 | /1/           |   NULL |
|       2 |         1 | /1/2/         |   NULL |
|       3 |         2 | /1/2/3/       |      1 |
|       4 |         3 | /1/2/3/4/     |      1 |
|       8 |         4 | /1/2/3/4/8/   |      1 |
|       9 |         8 | /1/2/3/4/8/9/ |      1 |
|       7 |         4 | /1/2/3/4/7/   |      0 |
|       5 |         2 | /1/2/5/       |      0 |
|       6 |         5 | /1/2/5/6/     |      0 |
+---------+-----------+---------------+--------+

如何获得以下 PHP 数组：

[
    [
        'id' => 1,
        'parentId' => 0,
    ],
    [
        'id' => 2,
        'parentId' => 1,
        'nodes' => [
            [ // when branch == 0
                [
                    'id' => 5,
                    'parentId' => 2
                ],
                [
                    'id' => 6,
                    'parentId' => 5
                ],
            ],
            [ // when branch == 1
                [
                    'id' => 3,
                    'parentId' => 2
                ],
                [
                    'id' => 4,
                    'parentId' => 3,
                    'nodes' => [
                        [ // when branch == 0
                            [
                                'id' => 7,
                                'parentId' => 4
                            ],
                        ],
                        [ // when branch == 1
                            [
                                'id' => 8,
                                'parentId' => 4
                            ],
                            [
                                'id' => 9,
                                'parentId' => 8
                            ],
                        ]
                    ]
                ],
            ]
        ]
    ]
]

该功能应该具有无限的深度。

任何帮助将不胜感激，因为我一直在碰壁。

Answer 1

类似这样的：

function buildTree($arr, $parentID)
{
    $children = [];
    foreach ($arr as $item) {
        if ($item['parent_id'] == $parentID) {
            array_push($children, [
                'id'       => $item['node_id'],
                'parentId' => $item['parent_id'],
                'nodes'    => buildTree($arr, $item['node_id'])
            ]);
        }
    }

    return $children;
}

$tree = buildTree($flat, null);

更新：

function getBranches($arr, $parentID)
{
    $branches = array();

    foreach ($arr as $item) {
        if ($item['parent_id'] == $parentID) {

            $bKey = $item['branch'];
            $node = array(
                'id'       => $item['node_id'],
                'parentId' => $item['parent_id']
            );

            $firstNodeChild = false;
            if ($nodeChildren = getBranches($arr, $item['node_id'])) {
                $hasKey = array_key_exists($bKey, $nodeChildren);
                if ($hasKey && $nodeChildren[$bKey]) {
                    if (sizeof($nodeChildren[$bKey]) == 1) {
                        $firstNodeChild = $nodeChildren[$bKey][0];
                        unset($nodeChildren[$bKey]);
                    }
                }
                if ($nodeChildren) {
                    $node['nodes'] = $nodeChildren;
                }
            }
            if (!array_key_exists($bKey, $branches)) {
                $branches[$bKey] = array();
            }
            $branches[$bKey][] = $node;
            if (false !== $firstNodeChild) {
                $branches[$bKey][] = $firstNodeChild;
            }

        }
    }
    ksort($branches);

    return $branches;
}

$tree = getBranches($arr, 0);