将修改后的预排序树遍历数据放入数组 [英] Getting Modified Preorder Tree Traversal Data into an Array

问题描述

将树数据放入数组的有效方法是什么?

What is an efficient way to put the tree data into an array?

我遵循了站点指南来检索树数据.

I followed the sitepoint tutorial to retrieve the tree data.

但是，本教程仅显示如何输出树，而不显示如何创建多维数组.

However, the tutorial only shows how to output the tree, not how to make a multidementional array.

我用过

SELECT title, lft, rgt FROM tree_structure WHERE lft BETWEEN $parentLft  AND $parentRgt ORDER BY lft ASC

因此，对于每个项目，我都有其标题，左侧和右侧的值.

So for each item, I have its title, left and right values.

我一直坚持让数组看起来像这样

I am stuck on making the array look like this

Array
(
 Title: Main Topic
 Children => Array
             (
              => Title: subTopic
                     Leaf:  true
              => Title: Another subtopic
                     Children =>  Array
                               (
                                => Title: subtopic child
                                  Leaf: true
                               )
              ) 

)

如果您能提供帮助，我将非常感谢.

If you could help, I would really appreciate it.

PS. sql输出看起来像这样的 (除了我有标题，没有名称，不要使用category_id):

PS. The sql output looks like this (except I have title, not name and don't use category_id ):

+-------------+----------------------+-----+-----+
| category_id | name                 | lft | rgt |
+-------------+----------------------+-----+-----+
|           1 | ELECTRONICS          |   1 |  20 |
|           2 | TELEVISIONS          |   2 |   9 |
|           3 | TUBE                 |   3 |   4 |
|           4 | LCD                  |   5 |   6 |
|           5 | PLASMA               |   7 |   8 |
|           6 | PORTABLE ELECTRONICS |  10 |  19 |
|           7 | MP3 PLAYERS          |  11 |  14 |
|           8 | FLASH                |  12 |  13 |
|           9 | CD PLAYERS           |  15 |  16 |
|          10 | 2 WAY RADIOS         |  17 |  18 |

推荐答案

将此代码提供帮助. $ results是数据库结果. $ tree是您要返回的数组.

Give this code a shot. $results is the database results. $tree is the array you're getting back.

function create_tree ($results) {

    $return = $results[0];
    array_shift($results);

    if ($return['lft'] + 1 == $return['rgt'])
        $return['leaf'] = true;
    else {
        foreach ($results as $key => $result) {
            if ($result['lft'] > $return['rgt']) //not a child
                break;
            if ($rgt > $result['lft']) //not a top-level child
                continue;
            $return['children'][] = create_tree(array_values($results));
            foreach ($results as $child_key => $child) {
                if ($child['rgt'] < $result['rgt'])
                    unset($results[$child_key]);
            }
            $rgt = $result['rgt'];
            unset($results[$key]);
        }
    }

    unset($return['lft'],$return['rgt']);
    return $return;

}
$tree = create_tree($results);

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