Problem outputting tree hierarchy.

[TeNDoLLA]

Hi,
So here is the deal. I get results from database in array which is something like this:

Array
(
    [0] => Array
        (
            [feature_name] => test parent 1
            [feature_id] => 883
            [parent_feature_id] => 0
        )

    [1] => Array
        (
            [feature_name] => child 1
            [feature_id] => 884
            [parent_feature_id] => 883
        )

    [2] => Array
        (
            [feature_name] => child 1-2
            [feature_id] => 885
            [parent_feature_id] => 883
        )

    [3] => Array
        (
            [feature_name] => test parent 2
            [feature_id] => 886
            [parent_feature_id] => 0
        )

    [4] => Array
        (
            [feature_name] => child 2-1
            [feature_id] => 887
            [parent_feature_id] => 886
        )

    [5] => Array
        (
            [feature_name] => child 2-2
            [feature_id] => 888
            [parent_feature_id] => 886
        )

    [6] => Array
        (
            [feature_name] => test feature without children
            [feature_id] => 889
            [parent_feature_id] => 0
        )

    [7] => Array
        (
            [feature_name] => grandchild-1-1
            [feature_id] => 890
            [parent_feature_id] => 884
        )

    [8] => Array
        (
            [feature_name] => grandchild-1-2
            [feature_id] => 891
            [parent_feature_id] => 884
        )

)

And from this result set I would need to print out a tree hierarchy which is not dependant on the level of the deepness nor the amount of the branches in the tree. Here is what I try to achieve for the current example result set:

o test parent 1
   - child 1
      * grandchild 1-1
      * grandchild 1-2
   - child 1-2
o test parent 2
   - child 2-1
   - child 2-2
o testi feature without children

So I have tried now few days to create some sort of loops and recursive function that would do this but the output has always been a mess or wrong. Anyone know how to to do this? Any help and piece of advice is warmly welcome. Thanks in advance.


-TeNDoLLA

[iulian]

The following code should work.

<?php
$source = array(
    array('id' => 1,    'feature' => 'f1',        'parent_feature_id' => 0),
    array('id' => 2,    'feature' => 'f1.1',        'parent_feature_id' => 1),
    array('id' => 3,    'feature' => 'f1.1.1',    'parent_feature_id' => 2),
    array('id' => 4,    'feature' => 'f2',        'parent_feature_id' => 0),
    array('id' => 5,    'feature' => 'f1.1.2',    'parent_feature_id' => 2),
);

$map = array();
for ($i = 0, $n = count($source); $i < $n; $i++) {
    $source[$i]['children'] = array();
    $map[$source[$i]['id']] = $i;
}

$tree = array();
for ($i = 0; $i < $n; $i++) {
    $node = $source[$i];
    if (0 == $node['parent_feature_id']) {
        $tree[] = &$source[$i];
    }
    else {
        $source[$map[$node['parent_feature_id']]]['children'][] = &$source[$i];
    }
}

var_dump($tree);        // this is your tree

?>