PHP: Building a hierarchistic array structure - php

Question

I'm having some problems building an hierarchistic array structure - I have almost got it done, but there's something unexplained that makes my array look weird which I hoped you could help me with.
The tree structure is:
root
|data
|-children
|--data
|--children
|---data
|---children
Any child can have any number of children and each child can have any number of parents.
I have a function that builds the tree:
private function build_tree($rows,$parent) {
$i = 0;
$response -> result = array();
$result = array();
$leaf = false;
foreach($rows as $row) {
if($row['parent_id'] == $parent) {
$leaf = is_null($row['treeDef']) ? false : true;
$workingSet = array_merge($result,array(
'id' => (int)$i,
'parent_id' => (int)$row['parent_id'],
'child_id' => (int)$row['id'],
'name' => (string)$row['resourceName'],
'updated' => strtotime($row['updated']),
'purchasedUnit' => (string)$row['purchasingUnit'],
'purchasedCost' => (double)$row['purchasingCosts'],
'purchasedDiscount' => (double)$row['discount'],
'estimateUnit' => (string)$row['estimatingUnit'],
'profitAddOn' => (string)$row['profitAddOn'],
'landedCost' => (double)$row['landedCost'],
'unitCorrelation' => (double)$row['unitCorrelation'],
'leadTime' => (string)$row['leadTime'],
'ResourceClassShortname' => (string)$row['ResourceClassShortname'],
'supplierName' => (string)$row['nameSupplier'],
'iconCls' => (string)$row['typeIcon'],
'leaf' => $leaf
));
$hasChildren = $this->Resource_model->has_children($rows,$row['id']);
if ($hasChildren->check) {
if (!$leaf) {
for($j=0; $j <= ($hasChildren -> rows); $j++) {
$parentArray = $workingSet;
$childArray = $this -> Resource_model -> build_tree($rows,$row['id']);
$workingSet = array_merge($parentArray,array('children' => $childArray -> result));
}
}
}
$result[$i] = $workingSet;
$i++;
}
}
$response -> result = $result;
$response -> rows = $i;
return $response;
}
Which produces this JSON:
Big picture
Every item that has 2 children (or more? - no test values) gets the first item like it should be, but the second item contains the first item as well - duplicating all the results.
Any help appreciated.

Answer 1

Instead of array_merge use array_push - this will add the children subarray instead of trying merging it with the one already existing...
It's in this part of code (already edited):
$hasChildren = $this->Resource_model->has_children($rows,$row['id']);
if ($hasChildren->check) {
if (!$leaf) {
for($j=0; $j <= ($hasChildren->rows); $j++) {
$parentArray = $workingSet;
$childArray = $this->Resource_model->build_tree($rows,$row['id']);
$workingSet = array_push($parentArray,array('children' => $childArray->result));
}
}
}

Answer 2

Made it work, here's the final code:
private function build_tree($rows,$parent) {
$i = 0;
$response -> result = array();
$result = array();
$leaf = false;
$newArray = array();
foreach($rows as $row) {
if($row['parent_id'] == $parent) {
$leaf = is_null($row['treeDef']) ? false : true;
$newArray = array(
'id' => (int)$i,
'parent_id' => (int)$row['parent_id'],
'child_id' => (int)$row['id'],
'name' => (string)$row['resourceName'],
'updated' => strtotime($row['updated']),
'purchasedUnit' => (string)$row['purchasingUnit'],
'purchasedCost' => (double)$row['purchasingCosts'],
'purchasedDiscount' => (double)$row['discount'],
'estimateUnit' => (string)$row['estimatingUnit'],
'profitAddOn' => (string)$row['profitAddOn'],
'landedCost' => (double)$row['landedCost'],
'unitCorrelation' => (double)$row['unitCorrelation'],
'leadTime' => (string)$row['leadTime'],
'ResourceClassShortname' => (string)$row['ResourceClassShortname'],
'supplierName' => (string)$row['nameSupplier'],
'iconCls' => (string)$row['typeIcon'],
'leaf' => $leaf
);
$hasChildren = $this -> Resource_model -> has_children($rows,$row['id']);
if ($hasChildren->check) {
for($j=0; $j <= ($hasChildren -> rows); $j++) {
$childArray = $this -> Resource_model -> build_tree($rows,$row['id']);
$newArray = array_merge($newArray, array('children' => $childArray -> result));
}
}
$result[$i] = $newArray;
$i++;
}
}
$response -> result = $result;
$response -> rows = $i;
return $response;
}