PHP multi dimensional array find all unique paths - php

Question

I have a PHP multi-dimensional array organized with each node listing its parent nodes under it. I'm trying to transform the array so that the output lists hierarchically with each node listing any child nodes and only listing unique paths within the array.
for instance this input array:
$input = [
[
"name" => "home",
"parents" => [],
],
[
"name" => "newslist",
"parents" => [
[
"name" => "home",
"parents" => [],
],
],
],
[
"name" => "newsdetail",
"parents" => [
[
"name" => "newslist",
"parents" => [
[
"name" => "home",
"parents" => [],
],
],
],
[
"name" => "home",
"parents" => [],
],
],
],
[
"name" => "knowledge",
"parents" => [],
],
];
Should output this array:
$output = [
[
"name" => "home",
"children" => [
[
"name" => "newslist",
"children" => [
[
"name" => "newsdetail",
"children" => [],
],
],
],
],
],
[
"name" => "knowledge",
"children" => [],
],
];

Answer 1

This could probably be done in a much nicer way, but this method works. just procedural functions as a proof of concept.
<?php
$input = [
[
"name" => "home",
"parents" => [],
],
[
"name" => "newslist",
"parents" => [
[
"name" => "home",
"parents" => [],
],
],
],
[
"name" => "newsdetail",
"parents" => [
[
"name" => "newslist",
"parents" => [
[
"name" => "home",
"parents" => [],
],
],
],
[
"name" => "home",
"parents" => [],
],
],
],
[
"name" => "knowledge",
"parents" => [],
],
];
//recursively get all parents and the level the parent is at
function getParents($nodes,$level,&$parents)
{
foreach($nodes AS $key => $node)
{
$parents[ $node['name'] ] = array( "name" => $node['name'], "level" => $level);
if(isset($node['parents']) && !empty($node['parents']))
{
$level += 1;
getParents($node['parents'],$level,$parents);
}
}
}
//sort the parents by level
function sortParentsByLevel($a, $b)
{
if ($a['level'] == $b['level']) {
return 0;
}
return ($a['level'] > $b['level']) ? -1 : 1;
}
//find the output path based on parents array to add new value to
function setValueFromPath(&$paths, $parents, $value)
{
$dest = &$paths;
if(empty($parents))
{
if(!isset($dest[$value]))
$dest[$value] = array();
} else {
$finalNode = array_pop($parents);
foreach ($parents as $parent)
{
$dest = &$dest[$parent];
}
$dest[$finalNode][$value] = array();
}
}
//init new variable
$output = array();
//loop through each input node
foreach($input AS $key => $node)
{
//init a parent array
$parents = array();
//if we have parents use the getParents method to set them
if(isset($node['parents']) && is_array($node['parents']) && !empty($node['parents']))
{
getParents($node['parents'],1,$parents);
}
//sort the parents according to their level
uasort($parents, 'sortParentsByLevel');
//we're only interested in the associative key
$parentKeys = array();
foreach($parents AS $parent)
{
$parentKeys[] = $parent['name'];
}
//add the $node['name'] value in the appropriate parent array
setValueFromPath($output, $parentKeys, $node['name'] );
}
echo '<pre>';
print_r($output);
echo '</pre>';
die();
/*
Array
(
[home] => Array
(
[newslist] => Array
(
[newsdetail] => Array
(
)
)
)
[knowledge] => Array
(
)
)
*/