PHP convert array of rows to tree-structured associative array

Question

I have the following table/PHP array;

 fileid | storage | parent |    name    | is_dir |        last_changed        |   size    | revision 
--------+---------+--------+------------+--------+----------------------------+-----------+----------
      1 |       1 |        | bunny.mov  | f      | 2016-05-17 12:20:45.430934 | 514832018 |      103
      2 |       1 |        | 10mb.bin   | f      | 2016-05-17 12:24:11.291796 |  10000000 |      104
      3 |       1 |        | 10mb.bin   | f      | 2016-05-17 12:28:16.867    |  10000000 |      105
      4 |       1 |        | bunny.mov  | f      | 2016-05-17 12:34:42.191069 | 514832018 |      106
      5 |       1 |        | miep2      | t      | 2016-05-17 12:38:09.286883 |      4096 |      107
      6 |       1 |      5 | bunny.mov  | f      | 2016-05-17 12:38:09.295631 | 514832018 |      107
      7 |       1 |        | miep2      | t      | 2016-05-17 12:48:25.375968 |      4096 |      108
      8 |       1 |      7 | bunany.mov | f      | 2016-05-17 12:48:25.384048 | 514832018 |      108

I would to get this data in an associative array, so I can build a tree-like structure. (file browser of some sorts, where each file has a list of revisions the user can pick)

So far, I have the following code;

private function rebuildStructure($files, $parent)
{
    $result = array();

    foreach ($files as $file){
        $entries = array();
        //get entries with $parent
        foreach ($files as $entry_file){
            if ($entry_file->parent == $file->id){
                array_push($entries, $this->rebuildStructure($files, $entry_file->fileid));
            }
        }
        array_push($result, array(
            'name' => $file->name,
            'entries' => $entries
        ));
    }
    return $result;
}

But this does however not work (infinite loop). Any ideas where I am going wrong? I'd like something along the lines of;

array(
    array( 'name' => 'miep2',
           'entries' => array( ...and repeat... )
    )
)

Any suggestions? Thank you!

You're calling the method within a for loop on the method, which indeed ends in an infinite loop. Also, why are you giving the $parent parameter to your function if you're not going to use it ;) — Loek
– Loek, Commented May 17, 2016 at 16:13

Miguel G. Flores · Accepted Answer · 2016-05-17 16:37:49Z

2

The intention of this code is to implement the solution in the simplest way, this is not efficient.

This aproach try to find all the children for every element in the array.

private function rebuildStructure($files, $parent)
{
    $result = array();

    foreach ($files as $file) {
        // I'm searching for some childs, and I'm not one of them.
        if (0 != $parent && $parent != $file->parent) continue;

        // I'm a child and we are searching just for "parents"
        if (!empty($file->parent) && 0 == $parent) continue;

        $entries = array();

        // Next nesting level, search for children
        array_push($entries, rebuildStructure($files, $file->fileid));

        array_push($result, array(
            'name' => $file->name,
            'entries' => $entries
        ));
    }

    return $result;
}

answered May 17, 2016 at 16:37

Miguel G. Flores

8127 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Niels Over a year ago

This works wonderfully, thank you @Miguel! What is, in your opinion, a more efficient way?

Miguel G. Flores Over a year ago

There is no need to use recursion on this problem and no need to iterate so many times over the array, with just one loop the tree could be done more efficiently.

Niels Over a year ago

Even if you do not know how deep it goes?

Loek · Accepted Answer · 2016-05-17 16:26:43Z

0

I've come up with this, it should work like you want it to.

private function rebuildStructure($files)
{
    $result = array();

    foreach ($files as $file)
    {
        $entries = array();

        foreach ($files as $entry_file)
        {
            if ($entry_file->parent === $file->id)
            {
                $nestedArray = array();
                array_push($nestedArray, $entry_file);
                array_push($entries, $nestedArray);
            }
        }
        array_push($result, array(
            'name' => $file->name,
            'entries' => $entries
        ));
    }
    return $result;
}

// Call this function to get the tree structure
public function getRebuildedStructure($files)
{
    return rebuildStructure($files);
}

answered May 17, 2016 at 16:26

Loek

4,15323 silver badges35 bronze badges

1 Comment

Miguel G. Flores Over a year ago

Seems like the original problem was meant to use recursion, in this case two level nesting won't work.

Collectives™ on Stack Overflow

PHP convert array of rows to tree-structured associative array

2 Answers 2

3 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related