Build hierarchical list from array

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)

Barmar · Accepted Answer · 2013-05-01 17:49:46Z

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], "\n";
}

answered May 1, 2013 at 17:49

Barmar

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Comments

nice ass · Accepted Answer · 2013-05-01 16:54:29Z

1

Count the number of slashes to generate the value prefixes, then sort by path (key) ?

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

ksort($output, SORT_STRING);

answered May 1, 2013 at 16:54

nice ass

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2 Comments

Barmar Over a year ago

Will this group items in the same part of the hierarchy together? E.g. if you have 1/2, 1/5, 1/2/3, 1/2/4, 1/5/6, 1/5/7.

nice ass Over a year ago

Yes, isn't that the intended output? (1/2, 1/2/3, 1/2/4, 1/5...)

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