从数组构建分层列表

Question

I have an array of categories that looks something like

array(
  array(
    'id' => '1',
    'path' => '1',
    'children_count' => '16',
    'name' => 'A'
  ),
  array(
    'id' => '3',
    'path' => '1/2/3',
    'children_count' => '0',
    'name' => 'C'
  ),
  array(
    'id' => '2',
    'path' => '1/2',
    'children_count' => '9',
    'name' => 'B'
  ),
  array(
    'id' => '4',
    'path' => '1/2/4',
    'children_count' => '0',
    'name' => 'D'
  )
)

What I'm trying to build is a hierarchal array (the path key shows the relation based on id), so the output is in the correct order (root parent first, then children, then more children) and indent the name based on how far down in the child is. The end result should look something like:

A
-B
--C
--D

Here's what I have so far, but it's obviously not working

$categoryTree = array();

foreach ($categories as $category) {

    $categoryTree[(string)$category['path']] = str_repeat("-", substr_count($category['path'], "/")) . $category['name'];
}

ksort($categoryTree);

var_export($categoryTree);

Which comes out to:

array (
  '1/2' => '-B',
  '1/2/3' => '--C',
  '1/2/4' => '--D',
  1 => 'A'
)

How can I get these in the correct order? (and if siblings could be ordered by id that would be dandy too)

Answer 1

This is based on One Trick Pony's answer, but correctly handles IDs with more than one digit.

foreach ($categories as $category)
  $output[$category['path']] =
    str_repeat('-', substr_count($category['path'], '/')) . $category['name'];

$paths = array_keys($output);
natsort($paths);

foreach ($paths as $path) {
  echo $output[$path], "
";
}