如何用PHP将内部数组展开为多维数组并保留关联键值？

问题 #

我尝试读取文件内容并存入数组，文件以日期命名，但单个文件中可能包含多个价格。我使用explode函数拆分字符串并存入数组，目前遇到的问题是不知道如何将内部的价格数组展开到外层数组，同时保留date和fruit等其他键值对。

现有代码：

foreach( $paths as $item => $wishlist ){
   foreach( $wishlist as $k => $v ){
      $file = basename($v);
      $info = pathinfo($file);
      $file_name = basename($file,'.'.$info['extension']);
      $array[$k]['date'] = $file_name;
      $array[$k]['fruit'] = $v;
      $content = nl2br(file_get_contents($v));
      $words = explode($file_name, $content);
      $array[$k]['price'] = $words;
   }
}

当前输出：

[{"date":"2023-06-01", "fruit":"apple", "price":["2", "4", "6"] },
{"date":"2023-06-02", "fruit":"orange", "price":["5", "7"] },
{"date":"2023-06-03", "fruit":"mango", "price":["11", "12", "8"] }]

期望输出：

[{"date":"2023-06-01", "fruit":"apple", "price": "2" },
{"date":"2023-06-01", "fruit":"apple", "price": "4" },
{"date":"2023-06-01", "fruit":"apple", "price": "6" },
{"date":"2023-06-02", "fruit":"orange", "price": "5" },
{"date":"2023-06-02", "fruit":"orange", "price": "7" },
{"date":"2023-06-03", "fruit":"mango", "price": "11" },
{"date":"2023-06-03", "fruit":"mango", "price": "12" },
{"date":"2023-06-03", "fruit":"mango", "price": "8" }]

解决方案 #

你需要遍历拆分后的价格数组，为每个价格单独创建一条记录，保留对应的date和fruit信息。修改后的代码如下：

// 初始化空数组存储最终结果
$result = [];

foreach( $paths as $item => $wishlist ){
   foreach( $wishlist as $k => $v ){
      $file = basename($v);
      $info = pathinfo($file);
      $file_name = basename($file,'.'.$info['extension']);
      // 提取基础信息作为模板
      $baseData = [
          'date' => $file_name,
          'fruit' => $v
      ];
      $content = nl2br(file_get_contents($v));
      $words = explode($file_name, $content);
      
      // 遍历每个价格，生成独立记录
      foreach($words as $price){
          // 过滤空值，避免无效条目
          $cleanPrice = trim($price);
          if($cleanPrice !== ''){
              $result[] = array_merge($baseData, ['price' => $cleanPrice]);
          }
      }
   }
}

改动说明 #

1. 新增$result数组专门存储展开后的最终结果，避免原数组的索引冲突问题
2. 将date和fruit存入$baseData作为基础模板，减少重复代码
3. 遍历拆分得到的价格数组，为每个非空价格创建新数组条目，合并基础信息与单个价格
4. 增加trim()处理，去除价格前后的空白字符（换行、空格等），确保数据干净

内容的提问来源于stack exchange，提问作者pyeoh 17