Convert flat array with dot-delimited keys to nested array

Question

I am trying to created nested array from flat based on its keys. Also format of keys in original array can be changed if it will simplify task.

From :

$arr = [
 'player.name' => 'Joe',
 'player.lastName' => 'Snow',
 'team.name' => 'Stars',
 'team.picture.name' => 'Joe Snow Profile',
 'team.picture.file' => 'xxx.jpg'
 ];

To:

$arr = [
 'player' => [
 'name' => 'Joe'
 , 'lastName' => 'Snow'
 ]
 ,'team' => [
 'name'=> 'Stars'
 ,'picture' => [
 'name' => 'Joe Snow Profile'
 , 'file' =>'xxx.jpg'
 ]
 ],
 ];

• Santosh: you need to convert in existing array or you have to create new array.
• Santosh: from array you have already exist ?
• Santosh: player.name is a single key ?
• Alex Kneller: if you dont have . after it it single key else its group to be nested
• Ben: My edited answer should fit but is very static. If you need a deeper recursion there would be another way.

Answer 1

Here is my take on it.
It should be able to handle arbitrary depth

function unflatten($arr) {
 $result = array();
 foreach($arr as $key => $value) {
 $keys = explode(".", $key); //potentially other separator
 $lastKey = array_pop($keys);
 $node = &$result;
 foreach($keys as $k) {
 if (!array_key_exists($k, $node))
 $node[$k] = array();
 $node = &$node[$k];
 }
 $node[$lastKey] = $value;
 }
 return $result;
}

• user5051310: Building out a multi-dimensional array as if it were a tree? This answer deserves more upvotes

Answer 2

Combination of iteration and recursion. Could be simplified to just iterative.

$array = [
 'player.name' => 'Joe',
 'player.lastName' => 'Snow',
 'team.name' => 'Stars',
 'team.picture.name' => 'Joe Snow Profile',
 'team.picture.file' => 'xxx.jpg'
];
$newArray = array ();
foreach($array as $key=> $value) {
 $temp = array ();
 $keys = array_reverse (explode('.', $key));
 $temp[$keys[0]] = $value;
 for ($i = 1; $i < count($keys); $i++) {
 $temp[$keys[$i]] = $temp;
 unset ($temp [$keys [$i -1]]);
 }
 $newArray = array_merge_recursive($newArray,$temp);
}
var_dump($newArray );

• Alex Kneller: Thanks, very elegant solution.
• Alex Kneller: You are right your answer was more readable,but Anly's have better performance.

Answer 3

I received this question as a test, this is my answer:

<?php
function buildArray(&$newArray, $keys, $value)
{
 if (sizeof($keys) == 0) {
 return $value;
 } else {
 $key = array_shift($keys);
 if (isset($newArray[$key])) {
 $value = buildArray($newArray[$key], $keys, $value);
 if (is_array($value)) {
 $newArray[$key] += $value;
 } else {
 $newArray[$key] = $value;
 }
 $arr = $newArray;
 } else {
 $arr[$key] = buildArray($newArray, $keys, $value);
 }
 }
 return $arr;
}
$arr = [
 'player.name' => 'Joe',
 'player.lastName' => 'Snow',
 'team.name' => 'Stars',
 'team.picture.name' => 'Joe Snow Profile',
 'team.picture.file' => 'xxx.jpg',
];
$newArray = [];
foreach ($arr as $key => $value) {
 $explodedKey = explode(".", $key);
 $temp = buildArray($newArray, $explodedKey, $value);
 $newArray = array_merge($temp, $newArray);
}
print_r($newArray);
?>

Answer 4

You could do it like this

$newArr = []; 
for ($arr as $key => $val) {
 $tmp = explode ('.', $key);
 if (!array_key_exists ($tmp [0], $newArray){
 $newArray [$tmp [0]] = [];
 }
 $newArray [$tmp [0]][$tmp [1]] = $val;
 } 

edit: Damn didn't saw the third level in team.
Not very generic but should work for third level ;)

$newArr = []; 
for ($arr as $key => $val) {
 $tmp = explode ('.', $key);
 if (!array_key_exists ($tmp [0], $newArray){
 $newArray [$tmp [0]] = [];
 }
 if (count($tmp) > 2){
 if (!array_key_exists ($tmp [1], $newArray[$tmp [0]]){
 $newArray [$tmp [0]][$tmp[1]] = [];
 }
 $newArray [$tmp [0]][$tmp [1]][$tmp [2]] = $val;
 } else {
 $newArray [$tmp [0]][$tmp [1]] = $val;
 }
 } 

• Alex Kneller: thanks ,but as i comment for another answer it have unlimited levels.
• Ben: Ok. You could try it with a recursive function and split up first part of the string in every recursion. I have to leave now in 5 hours i could write you an example ;)

Answer 5

I think you can use something like this, for converting 2d array to nested tree. But You'll have to play with parent_id

https://github.com/denis-cto/flat-array-to-nested-tree

• mate00: Please don't post just plain URLs without explanation and posting some code.