Grouping multi-dimensional arrays in PHP - php

Question

I can't focus right now and my mind keeps playing tricks on me with the solution to this.
I've tried a multitude of options but they keep not working.. Sigh.
Say I have a string as such; a.b.c|a.b.d|a.b.e|f|f.g|f.h|i, I want to create a new array (or object) as the following
A > B > C, D, E
F > G, H
I
With > being a nested array, , being an element in the parent array.
These should be able to continue nesting a multitude of times, e.g. A > B > C > D > E > F, D
Any guidance? I've tried exploding the string and then those strings to an array - this array holds A > B > C, A > B > D, A > B > E etc., I just can't get my head around to how to combine them efficiently.
I started with just looping over each element in the array and checking if the parents' key exists, but that was failing. Any help is appreciated as I'm incredibly tired, quite shocking I can do such a simple task.

Answer 1

<?php
// read line from standard input
$line = trim(fgets(STDIN));
echo "Line: $line\n"; // debug
// split lines by |
$segments = explode('|', $line);
print_r($segments); // debug
// prepare output array
$md_array = array();
// walk through the segments
foreach($segments as $segment) {
// set pointer to output array
$current = &$md_array;
// split segment by .
$tokens = explode('.', $segment);
print_r($tokens); // debug
foreach($tokens as $token) {
echo "working on $token\n";
// if key is not included in the array, create empty array
if( ! array_key_exists($token, $current) ) {
$current[$token] = array();
}
// pass the pointer to following sub-section
$current = &$current[$token];
}
}
// print out the output
print_r($md_array);
?>
Testing the script
echo "a.b.c|a.b.d|a.b.e|f|f.g|f.h|i" | php test.php
Output
Array
(
[a] => Array
(
[b] => Array
(
[c] => Array
(
)
[d] => Array
(
)
[e] => Array
(
)
)
)
[f] => Array
(
[g] => Array
(
)
[h] => Array
(
)
)
[i] => Array
(
)
)

Answer 2

Want to thank Richard for his solution, which allowed me to achieve my aim.
See the code below:
public static function permissions($permList) {
$segments = explode('|', $permList);
$md_array = array();
foreach($segments as $segment) {
$current = &$md_array;
$tokens = explode('.', $segment);
$x = 0;
foreach($tokens as $token) {
if(!array_key_exists($token, $current) ) {
if(count($tokens) > $x+1)
$current[$token] = array();
else
$current[] = $token;
}
if(count($tokens) > $x+1)
$current = &$current[$token];
$x++;
}
}
return $md_array;
}
If I input a.b.c|a.b.d|a.b.e|f|f.g|f.h|i, I am returned with the expected output above.
Many thanks.