how to add child array with dynamic key in loop PHP - php

Question

i have string like this
$string = 'root.1.child1.2.nextnode.3.anothernode.4.var';
exploded by "." and created array like this
$arr = array('root','1','child1','2','nextnode','3','anothernode','3','var');
how i can convert this array to something like this ?
it should be dynamically convert because in some cases nodes in string are in a number different with the sample .
["root"]=>
array(1) {
[1]=>
array(1) {
["child1"]=>
array(1) {
[2]=>
array(1) {
["nextnode"]=>
array(1) {
[3]=>
array(1) {
["anothernode"]=>
array(1) {
[3]=>
array(1) {
[var]=>
NULL
}
}
}
}
}
}
}
}

Answer 1

An example using recursive function.
$array = ['root', '1', 'child1', '2', 'nextnode', '3', 'anothernode', '3', 'var'];
function getNestedArray(array $arr, int $idx = 0) {
if ($idx + 1 <= count($arr)) {
return [$arr[$idx] => getNestedArray($arr, $idx + 1)];
}
return null;
}
$output = getNestedArray($array);
var_dump($output);

Answer 2

This can be quit easily achieved by referencing the output and looping over the exploded array:
$output = [];
$reference = &$output;
foreach ($arr as $el) {
if (is_numeric($el)) {
$el = (int)$el;
}
$reference = [];
$reference[$el] = null;
$reference = &$reference[$el];
}
This also checks whether the element is a number and casts it to an integer if it is. The $output variable will contain the final array.

Answer 3

You can use recursive function
to do though
$flatArray = array('root','1','child1','2','nextnode','3','anothernode','3','var'); // your array
function createNestedArray($flatArray)
{
if( sizeof($flatArray) == 1 ) {
return [ $flatArray[0] => null ]; // for the case that paramter has one member we need to return [ somename => null ]
}
$nestedArray[ $flatArray[0] ] = createNestedArray(array_slice($flatArray, 1)); // otherwise we need to call createNestedArray with rest of array
return $nestedArray;
}
$nestedArray = createNestedArray($flatArray); // the result