PHP实现下划线分隔层级数组转换为多层JSON结构

核心思路 #

不用按层级拆分多次遍历数组，直接遍历每个层级字符串，通过引用指针动态定位到嵌套结构的对应层级，自动创建中间节点，最后一层节点直接赋值为同名字符串即可，天然支持任意深度的层级，无需硬编码层级判断逻辑。

完整可运行代码 #

// 替换为你实际的数据源
$subsectorTags = [
    'Business Services',
    'Business Services_Consulting',
    'Business Services_Foodservice Distribution',
    'Business Services_Information Services',
    'Consumer',
    'Consumer_Consumer Discretionary',
    'Consumer_Consumer Discretionary_Apparel, Footwear & Accessories',
    'Consumer_Consumer Discretionary_Apparel, Footwear & Accessories_Activewear',
    'Consumer_Consumer Discretionary_Apparel, Footwear & Accessories_Apparel',
    'Consumer_Consumer Discretionary_Apparel, Footwear & Accessories_Footwear',
    'Consumer_Consumer Discretionary_Apparel, Footwear & Accessories_Luxury Goods',
    'Consumer_Consumer Discretionary_Broadline Retail',
    'Consumer_Consumer Discretionary_Consumer Services',
    'Consumer_Consumer Discretionary_Consumer Services_Child Care',
    'Consumer_Consumer Discretionary_Consumer Services_Fitness Services/Gyms',
    'Consumer_Consumer Discretionary_Gaming, Lodging & Leisure',
    'Consumer_Consumer Discretionary_Gaming, Lodging & Leisure_Cruise Lines',
    'Consumer_Consumer Discretionary_Gaming, Lodging & Leisure_Gaming',
    'Consumer_Consumer Discretionary_Gaming, Lodging & Leisure_Live Entertainment',
    'Consumer_Consumer Discretionary_Gaming, Lodging & Leisure_Lodging',
    'Consumer_Consumer Discretionary_Gaming, Lodging & Leisure_Online Sports Betting',
    'Consumer_Consumer Discretionary_Gaming, Lodging & Leisure_Theme Parks',
    'Consumer_Consumer Discretionary_Recreational Products',
    'Consumer_Consumer Discretionary_Recreational Products_Fitness Equipment',
    'Consumer_Consumer Discretionary_Recreational Products_Recreational Vehicles',
    'Consumer_Consumer Discretionary_Recreational Products_Sporting Goods - Recreational Products',
    'Consumer_Consumer Discretionary_Recreational Products_Toys',
    'Consumer_Consumer Discretionary_Restaurants',
    'Consumer_Consumer Discretionary_Restaurants_Casual Dining',
    'Consumer_Consumer Discretionary_Restaurants_Fast Casual',
    'Consumer_Consumer Discretionary_Restaurants_Full-Service Dining',
    'Consumer_Consumer Discretionary_Restaurants_Ghost Kitchen',
    'Consumer_Consumer Discretionary_Restaurants_QSR',
    'Consumer_Consumer Discretionary_Specialty Retail',
    'Consumer_Consumer Discretionary_Specialty Retail_Auto Retail',
    'Consumer_Consumer Discretionary_Specialty Retail_Auto Retail_Online Auto Marketplaces',
    'Consumer_Consumer Discretionary_Specialty Retail_Consumer Electronics',
    'Consumer_Consumer Discretionary_Specialty Retail_Food Retail',
    'Consumer_Consumer Discretionary_Specialty Retail_Home Furnishings',
    'Consumer_Consumer Discretionary_Specialty Retail_Home Improvement',
    'Consumer_Consumer Discretionary_Specialty Retail_Sporting Goods - Specialty Retail',
    'Consumer_Consumer Staples',
    'Consumer_Consumer Staples_Household & Personal Products',
    'Consumer_Consumer Staples_Household & Personal Products_Beauty & Cosmetics',
    'Consumer_Consumer Staples_Household & Personal Products_Household Products',
    'Consumer_Consumer Staples_Packaged Food & Beverage',
    'Consumer_Consumer Staples_Packaged Food & Beverage_Beverage',
    'Consumer_Consumer Staples_Packaged Food & Beverage_Beverage _Energy Drinks',
    'Consumer_Consumer Staples_Packaged Food & Beverage_Packaged Food',
    'Consumer_Consumer Staples_Packaged Food & Beverage_Packaged Food_Alternative Protein',
    'Consumer_Consumer Staples_Tobacco / Cannabis',
    'Consumer_Consumer Staples_Tobacco / Cannabis_Cannabis',
    'Consumer_Consumer Staples_Tobacco / Cannabis_Tobacco',
];

$structure = [];
foreach ($subsectorTags as $item) {
    $parts = explode('_', $item);
    $totalLevel = count($parts);
    // 用引用跟踪当前操作的嵌套层级
    $currentNode = &$structure;
    foreach ($parts as $level => $nodeName) {
        // 最后一级直接赋值为 键名:值 同名
        if ($level === $totalLevel - 1) {
            $currentNode[$nodeName] = $nodeName;
            break;
        }
        // 中间级不存在则初始化空数组
        if (!isset($currentNode[$nodeName])) {
            $currentNode[$nodeName] = [];
        }
        // 移动指针到下一级
        $currentNode = &$currentNode[$nodeName];
    }
    // 销毁引用避免后续循环污染数据
    unset($currentNode);
}

// 打印符合要求的JSON格式
echo json_encode($structure, JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT);

方案优势 #

• 无层级限制：支持任意深度的下划线分隔层级，不需要提前知道层级数量，也不需要为不同层级写单独的处理逻辑
• 执行效率高：仅需要遍历一次原始数组，时间复杂度为O(N)（N为所有字符串的总字符数），远高于按层级多次遍历的方案
• 代码简洁：逻辑清晰无冗余，维护成本极低

内容的提问来源于stack exchange，提问作者arl