Php 如何按特定值对数组进行分组？

我有这样一个数组：

$files = array(
    "Input.txt" => "Randy",
    "Code.py" => "Stan",
    "Output.txt" => "Randy"
);

[
    "Randy" => ["Input.txt", "Output.txt"], 
    "Stan" => ["Code.py"]
]

<?php 
class FileOwners 
{
   public static function groupByOwners($files)
   {
       foreach ($files as $file => $owner){
          $data[$owner] = $file;
       };
       return $data;
   }
}
$files = array(
    "Input.txt" => "Randy",
    "Code.py" => "Stan",
    "Output.txt" => "Randy"
);
var_dump(FileOwners::groupByOwners($files));

我想按文件所有者对文件进行分组，并按如下方式返回：

$files = array(
    "Input.txt" => "Randy",
    "Code.py" => "Stan",
    "Output.txt" => "Randy"
);

[
    "Randy" => ["Input.txt", "Output.txt"], 
    "Stan" => ["Code.py"]
]

<?php 
class FileOwners 
{
   public static function groupByOwners($files)
   {
       foreach ($files as $file => $owner){
          $data[$owner] = $file;
       };
       return $data;
   }
}
$files = array(
    "Input.txt" => "Randy",
    "Code.py" => "Stan",
    "Output.txt" => "Randy"
);
var_dump(FileOwners::groupByOwners($files));

我试着这样做：

$files = array(
    "Input.txt" => "Randy",
    "Code.py" => "Stan",
    "Output.txt" => "Randy"
);

[
    "Randy" => ["Input.txt", "Output.txt"], 
    "Stan" => ["Code.py"]
]

<?php 
class FileOwners 
{
   public static function groupByOwners($files)
   {
       foreach ($files as $file => $owner){
          $data[$owner] = $file;
       };
       return $data;
   }
}
$files = array(
    "Input.txt" => "Randy",
    "Code.py" => "Stan",
    "Output.txt" => "Randy"
);
var_dump(FileOwners::groupByOwners($files));

---

请帮助如何创建它。

如果要覆盖$data，请使用

$data[$owner][]=$file

而不是

$data[$owner]=$file

public static function groupByOwners($files)
   {
       foreach ($files as $file => $owner){
          $data[$owner][] = $file;
       };
       return $data;
   }

只需创建一个多维数组
[]

foreach ($files as $file => $owner){
      $data[$owner][] = $file; // [] will store values as an array inside the key
} // Remove semicolon from here