PHP transform associative array of string in tree structure

Question

I have a list of path (just strings), like this:

$data = array(
    array('path' => 'foo/bar/baz'),
    array('path' => 'foo/bar/baz/qux'),
    array('path' => 'foo/bar'),
    array('path' => 'bar/baz/foo'),
    array('path' => 'baz'),
);

I would like to achieve a structure like this

Array
(
    [foo] => Array
        (
            [bar] => Array
                (
                    [baz] => Array
                        (
                            [qux] => null
                        )
                )
        )
    [bar] => Array
        (
            [baz] => Array
                (
                    [foo] => null
                )
        )
    [baz] => null
)

Side note

the structure displays only, non-common portions
the leaf would be null (null for me would be without children)

I know you will ask me what have you tried? the problem is: I don't know how to deal the problem in the right way

can you give me some advice, without massacre of downvote?

I don't see the pattern behind the array and the expected output. Because at the end you create: [baz] => but you already have one that begins with this. — Rizier123
– Rizier123, Commented Feb 2, 2015 at 19:16
@Rizier123 the leaf would be null (null for me would be without children) — Simone Nigro
– Simone Nigro, Commented Feb 2, 2015 at 19:18
You're trying to convert that array as it is into the desired array, right? — Caleb Lewis
– Caleb Lewis, Commented Feb 2, 2015 at 19:22

Isaac · Accepted Answer · 2015-02-02 19:44:34Z

2

I got pretty close, but instead of the endings being null, they're array's with size 0.

<?php

function ProcessPath($entry,$depth,&$current)
{
  if($depth<count($entry))
  {
    $key = $entry[$depth];
    if(!isset($current[$key]))$current[$key] = null;
    ProcessPath($entry,$depth+1,$current[$key]);
  }
}


$data = array(
  array('path' => 'foo/bar/baz'),
  array('path' => 'foo/bar/baz/qux'),
  array('path' => 'foo/bar'),
  array('path' => 'bar/baz/foo'),
  array('path' => 'baz'),
);
$result = null;
foreach($data as $path)
{
  ProcessPath(explode("/",$path['path']),0,$result);
}

print_r($result);

?>

output

Array
(
    [foo] => Array
        (
            [bar] => Array
                (
                    [baz] => Array
                        (
                            [qux] => 
                        )

                )

        )

    [bar] => Array
        (
            [baz] => Array
                (
                    [foo] => 
                )

        )

    [baz] => 
)

Essentially the function ProcessPath takes:

An array of the split path
The current depth eg: [foo] (0) or foo > [bar] (1) or foo > bar > [baz] (2)
A reference to where on the array the path is being put (denoted by &$reference

First off the function checks if the depth is within the current path being processed.

Then it extracts the $key to simplify the rest of the code.

This is where the magic happens, if the output hasn't got the current path segment set, it sets it.

The last line recurses onto the next element in the path $entry by taking the same $entry, increasing the $depth by 1, and changing the $current to the new section $current[$key].

edited Feb 2, 2015 at 19:44

answered Feb 2, 2015 at 19:31

Isaac

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5 Comments

Isaac Over a year ago

If this doesn't work, just change [] to array() (could be a language error)

Simone Nigro Over a year ago

thank you very much. I edited the answer to support old versions of php

Isaac Over a year ago

@SimoneNigro I just added a description to it so it probably would've cleared your edit. I added the array()s back in

Isaac Over a year ago

Aight I redid my edit again (didn't know that you could just whack a null in there). Should give you the desired output now

Simone Nigro Over a year ago

is perfect, I tried it and it does exactly what I wanted

Caleb Lewis · Accepted Answer · 2015-02-02 19:36:46Z

0

What you could do is iterate over the paths, explode the string of each path, and then add each value to the new array depending on the position of the value. If the value is the first, then it'll be the base. If it's the 2nd, then it goes in as a new array inside the first one, and so on.

answered Feb 2, 2015 at 19:36

Caleb Lewis

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