将平面数组转换为多维数组

Question

我有一个包含树数据的数组（按父 ID）。我想将其转换为多维数组。实现这一目标的最佳方法是什么？有没有什么短函数可以做到这一点？

源数组：

$source = array(
    '0' => array(
            'Menu' => array(
                    'id' => 45
                    'name' => 'Home'
                    'parent_id' => 1
            )
    )
    '1' => array(
            'Menu' => array(
                    'id' => 47
                    'name' => 'Get started'
                    'parent_id' => 1
            )
    )
    '2' => array(
            'Menu' => array(
                    'id' => 72
                    'name' => 'Attributes'
                    'parent_id' => 71
            )
    )
    '3' => array(
            'Menu' => array(
                    'id' => 73
                    'name' => 'Headings'
                    'parent_id' => 71
            )
    )
    '4' => array(
            'Menu' => array(
                    'id' => 75
                    'name' => 'Links'
                    'parent_id' => 71
            )
    )
    '5' => array(
            'Menu' => array(
                    'id' => 59
                    'name' => 'Images'
                    'parent_id' => 75
            )
    )
    '6' => array(
            'Menu' => array(
                    'id' => 65
                    'name' => 'Lists'
                    'parent_id' => 75
            )
    )
);

源数组中缺少一些父项。我希望缺少父项的项目成为根。结果数组：

$result = array(
    '0' => array(
            'Menu' => array(
                    'id' => 45
                    'name' => 'Home'
                    'parent_id' => 1
            )
            'Children' => array()
    )
    '1' => array(
            'Menu' => array(
                    'id' => 47
                    'name' => 'Get started'
                    'parent_id' => 1
            )
            'Children' => array()
    )
    '2' => array(
            'Menu' => array(
                    'id' => 72
                    'name' => 'Attributes'
                    'parent_id' => 71
            )
            'Children' => array()
    )
    '3' => array(
            'Menu' => array(
                    'id' => 73
                    'name' => 'Headings'
                    'parent_id' => 71
            )
            'Children' => array()
    )
    '4' => array(
            'Menu' => array(
                    'id' => 75
                    'name' => 'Links'
                    'parent_id' => 71
            )
            'Children' => array(
                    '0' => array(
                        'Menu' => array(
                            'id' => 59
                            'name' => 'Images'
                            'parent_id' => 75
                        )
                        'Children' => array()
                    )
                    '1' => array(
                        'Menu' => array(
                            'id' => 65
                            'name' => 'Lists'
                            'parent_id' => 75
                        )
                        'Children' => array()
                   )
            )
     )
);

更新：删除了方括号。

Answer 1

我认为 PHP 中没有内置函数可以做到这一点。

我尝试了以下代码，它似乎可以按照您描述的方式准备嵌套数组：

$nodes = array();
$tree = array();
foreach ($source as &$node) {
  $node["Children"] = array();
  $id = $node["Menu"]["id"];
  $parent_id = $node["Menu"]["parent_id"];
  $nodes[$id] =& $node;
  if (array_key_exists($parent_id, $nodes)) {
    $nodes[$parent_id]["Children"][] =& $node;
  } else {
    $tree[] =& $node;
  }
}

var_dump($tree);

我在为演示文稿编写的 PHP 类中编写了类似的算法 SQL 和 PHP 中的分层模型，但我使用的是对象而不是普通数组。

Answer 2

我编写此变体时考虑到 rootparent_id 为 0 或丢失。无论父母之后的孩子是否在 DB ($source) 中。

$source_by_id = array();
foreach ($source as &$row){
  $source_by_id[$row['id']] = &$row;
}
foreach ($source_by_id as $id => &$row){
  $source_by_id[ intval($row['parent_id']) ]['children'][$id] = &$row;
}
// remove cycling itself
unset($source_by_id[0]['children'][0]);

$result = $source_by_id[0]['children'];

结果数组键是适当的 id。享受！

Answer 3

我正在寻找如何使用类别来执行此操作的示例。此示例假设父母的父母 ID 始终为“0”。该示例使用 ZF2。

没有引用，也没有递归。诀窍在于输出中，您查找 [0] 索引，对于子项，您将parent_id 指定为索引。

$categoryLookup = $this->getCategoryLookup($associateById=true);

if ($assignedCategories) {          
    $categoryHeirarchy = array();
    foreach($assignedCategories as $assignedCategory) {
        $child = $categoryLookup[$assignedCategory->category_id];
        $parent = $categoryLookup[$child->parent_id];               
        $categoryHeirarchy[$child->parent_id][] = $categoryLookup[$child->category_id];
        $categoryHeirarchy[$parent->parent_id][$parent->category_id] = $categoryLookup[$parent->category_id];
    }           

    return $categoryHeirarchy;  
}


<h3>Categories</h3>
<dl class="dl-horizontal">
    <?php foreach($this->categoryHeirarchy[0] as $parent): ?>
        <dt><?php echo $this->escapeHtml($parent->name); ?></dt>
        <?php foreach($this->categoryHeirarchy[$parent->category_id] as $child): ?>
            <dd><?php echo $this->escapeHtml($child->name); ?></dd>
        <?php endforeach; ?>
    <?php endforeach; ?>                    
</dl>