如何在WordPress中将自定义文章类型的分类及子分类转为嵌套数组？

Got it, let's turn that flat database result into the nested structure you need. Here's a straightforward PHP solution tailored to your requirements:

Step 1: Sample Flat Data #

First, let's assume your database query returns an associative array like this (matches your table):

// This would come from your WordPress DB query
$flatCategories = [
    ['id' => 1, 'name' => 'categoryName', 'parent' => 0],
    ['id' => 2, 'name' => 'Name1', 'parent' => 1],
    ['id' => 3, 'name' => 'Name2', 'parent' => 1],
    // Optional: Add a sub-sub category to test deeper nesting
    ['id' => 4, 'name' => 'SubName1', 'parent' => 2],
];

Step 2: The Conversion Function #

This function will take your flat array and build the nested structure recursively:

function buildNestedCategories($flatCategories) {
    // Group categories by their parent ID for fast lookup
    $groupedByParent = [];
    foreach ($flatCategories as $category) {
        $groupedByParent[$category['parent']][] = $category;
    }

    // Recursive helper to build the tree
    $buildTree = function($parentId) use (&$buildTree, $groupedByParent) {
        $children = [];
        
        // Check if this parent has any child categories
        if (isset($groupedByParent[$parentId])) {
            foreach ($groupedByParent[$parentId] as $cat) {
                // Build the child entry, including its own children
                $childEntry = [
                    'id' => $cat['id'],
                    'name' => $cat['name'],
                    'children' => $buildTree($cat['id'])
                ];
                
                // Set children to empty string if there are no kids (per your example)
                if (empty($childEntry['children'])) {
                    $childEntry['children'] = '';
                }
                
                $children[] = $childEntry;
            }
        }
        
        return $children;
    };

    // Start building from top-level categories (parent ID = 0)
    return $buildTree(0);
}

Step 3: Usage & Result #

Call the function and output the nested array:

$nestedCategories = buildNestedCategories($flatCategories);
print_r($nestedCategories);

This will produce exactly the structure you want:

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => categoryName
            [children] => Array
                (
                    [0] => Array
                        (
                            [id] => 2
                            [name] => Name1
                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [id] => 4
                                            [name] => SubName1
                                            [children] => 
                                        )

                                )

                        )

                    [1] => Array
                        (
                            [id] => 3
                            [name] => Name2
                            [children] => 
                        )

                )

        )

)

Notes for WordPress #

If you're fetching the data directly via $wpdb, here's a sample query to get the category data in the right format:

global $wpdb;
$flatCategories = $wpdb->get_results(
    "SELECT term_id as id, name, parent 
     FROM {$wpdb->terms} t 
     JOIN {$wpdb->term_taxonomy} tt ON t.term_id = tt.term_id 
     WHERE tt.taxonomy = 'category'",
    ARRAY_A
);

This query joins the terms and term_taxonomy tables (WordPress's standard category storage) to get all the fields you need.

内容的提问来源于stack exchange，提问作者Pham Anh Thu