如何使用普通文件之前出现的子目录按字母顺序对目录内容进行排序？

Question

I need to sort the contents of a directory in ascending order (alphabetically). The directories must appear before files even if the directory's name would appear after a files name (alphabetically). The same way file explorers do, they list directories sorted then they list the files sorted.

I am using the following code which gives me a sorted list alphabetically but it does not advances the directories first:

if($handler = opendir($dir))
{
    while (($sub = readdir($handler)) !== FALSE)
    {
        // ...
    }    
    closedir($handler); 
}

Answer 1

A straightforward way to achieve that would be to populate an array with pairs like [is_file(path), path], sort this array (php will automatically sort by the first and then by the second element) and finally remove the is_file bit:

$path = 'somedir';
$dir = [];

// populate
foreach(glob("$path/*") as $f)
    $dir []= [is_file($f), $f];

// sort
sort($dir);

// remove
$dir = array_map('end', $dir);

// PROFIT
print_r($dir);