Question

I’m trying to add elements to a sub array of the sub array where they were added in the previous iteration, i.e. transforming this:

$a = array('a', 'b', 'c');

Into this:

$new_array = array(
    'a' => array(
        'b' => array(
            'c' => array()
        )
    )
);

Answer 1

$a = array('a', 'b', 'c');

$tmp = array_reverse($a);

$new_array = array();
foreach ($tmp as $item) { $new_array = array($item => $new_array); }