Question

My intent is to take a series of strings, explode them by “_” and use the keys from that array to build a “master” array.

My rules are:

if key no exists -> create key under parent array
if key exists -> add key as new array to parent
if key is last -> add value

String Examples

total_players_count
total_rosters_count
players_season1_count
players_season2_count
rosters_season1_count

Expected Results

$main = array(
    'total' => array(
        'players'   => array(
            'count' => '123',
        'rosters'   => array(
            'count' => '123')
        )
    ),
    'players' => array(
        'season1'   => array(
            'count' => '123'
        )
    )
);

I hope this shows what I’ve expected to write. Now let me lead into how I disappointed myself through a series of failures last night 😉

The gist is, my recursive functions haven’t been working so well so I’m not posting any of that code. I’ve been working with array_key_exists and that isn’t getting me my expected results. I came close using prev(), current(), and end() but the issue stems from an unexpected number of keys I have to parse through (otherwise I would just loop 3 times and be done. I know the following would work if I had a limited amount of keys to parse; but I don’t.

<?php
private function _get_section($parent_key, $sql) {

        $data = array();
        $data[$parent_key] = array();

        foreach ($sql AS $key => $value) {
            $keys       = explode('_', $key);

            if ($keys[0] == $parent_key) {
                $i          = 0;
                $total_keys = count($keys);

                for ($k = 1; $k < $total_keys; $k++) {
                    $i++;

                    if ($i == 1) {
                        echo '1. (' . $i . ') ' . $keys[$k];
                        $data[$parent_key][$keys[$k]] = array();
                    }
                    else if ($i > 1 && $i < $total_keys - 1) {
                        $data[$parent_key][$keys[$k - 1]][$keys[$k]] = array();
                    }
                    else if ($i == $total_keys - 1) {
                        $tmp = array_reverse($data);

                        // can't get the last key because I need to recursively loop 
                        // through the results to find where to set this last 
                        // key / value
                    }
                }
                $k      = 0;
                $i      = 0;
            }

            $keys       = array();
            $total_keys = 0;
        }
    }

Solution (thank you)

$tree = array();

foreach ($sql AS $key => $value) {
    $parts = explode('_', $key);

    $val = $value;

    foreach (array_reverse($parts) AS $part) {
        $val = array($part => $val);
    }
    $tree = array_merge_recursive($tree, $val);
}

Answer 1

untested. hopefully i didnt need to read your code to fully understand what you want, because i didnt. i just looked at the expected results + the input, although i wonder what happened to rosters_season1_count?

$tree = array();
foreach ($strings as $string) {
    $parts = explode('_', $string);
    $path = '123';
    foreach (array_reverse($parts) as $part) {
        $path = array($part => $path);
    }
    $tree = array_merge_recursive($tree, $path);
}