Creating a multidimensional array in PHP with indefinite depth

Question

Good Evening - I'm trying to create a multi-dimensional array based on a blown text string of account codes stored in a database. Account codes will have different lengths / depths. Say, for example, $ test in the array below is similar to the results that I would pull from a database:

$test = array( 
    '110|5100|120'    => 'Teacher Salaries',
    '110|5100|130'    => 'Other Professoinal Services',
    '110|5100|510|1'  => 'Primary Supplies',
    '110|5100|510|2'  => 'Intermediate Supplies', 
    '110|7300|110'    => 'Administrator Salaries', 
    '110|7300|510'    => 'Administrative Supplies', 
    '763|5100'        => 'Academic Grants'
); 
foreach($test AS $k => $v) { 
    $lvl = explode("|", $k);
    // Not sure what to do next... 
}

I want to create a function that will return an array, such as:

[110] => Array
    (
        [5100] => Array
            (
                [120] => Teacher Salaries
                [130] => Other Professional Services
                [510] => Array
                    (
                        [1] => Primary Supplies
                        [2] => Intermediate Supplies
                    )
            )
        [7300] => Array
            (
                [110] => Administrator Salaries
                [510] => Supplies
            )
    )
[763] => Array
    (
        [5100] => Academic Grants
    )

I was able to come up with a function that can take one of the codes and correctly break it into an array, but when I try to combine them together, they lose their keys. Here is what I still have:

function expandedArray($codes, $value) { 
    $decoded = explode("|",$codes);
    RETURN expandedArraySub($decoded, $value); 
}
function expandedArraySub($decoded = array(), $value = Null) { 
    $k = array_pop($decoded); 
    $out[$k] = $value;
    if(is_array($decoded) && count($decoded) > 0) { $out = expandedArraySub($decoded, $out); }
    RETURN $out;
}

But when I run the following, instead of getting what I want, as described above, I get an array that loses the key "110":

$r1 = expandedArray('110|5100|510|1', "Primary Supplies"); 
  // $r1 is now [ 110 => [5100 => [510 => [ 1 ] ] ] ]
$r2 = expandedArray('110|5100|510|2', 'Intermediate Supplies'); 
  // $r2 is now [ 110 => [5100 => [510 => [ 2 ] ] ] ]
$r = array_merge($r1, $r2); 

, , , . :

[0] => Array
    (
        [5100] => Array
            (
                [510] => Array
                    (
                        [1] => Primary Supplies
                    )
            )
    )
[1] => Array
    (
        [5100] => Array
            (
                [510] => Array
                    (
                        [2] => Intermediate Supplies
                    )
            )
    )

! !

Answer 1

:

function getVal($data,$chain){
    $level = $data;
    for($i=0;$i<count($chain);$i++){
        if(isset($level[$chain[$i]]))
            $level = $level[$chain[$i]];
        else
            return null; // key does not exist, return null
    }
    return $level;
}

function setVal(&$data,$chain,$value){
    $level = &$data;
    for($i=0;$i<count($chain);$i++){
        $level = &$level[$chain[$i]]; // set reference (&) in order to change the value of the object
    }
    $level = $value;
}

:

$output = array();
$test = array( 
    '110|5100|120'    => 'Teacher Salaries',
    '110|5100|130'    => 'Other Professoinal Services',
    '110|5100|510|1'  => 'Primary Supplies',
    '110|5100|510|2'  => 'Intermediate Supplies', 
    '110|7300|110'    => 'Administrator Salaries', 
    '110|7300|510'    => 'Administrative Supplies', 
    '763|5100'        => 'Academic Grants'
); 
foreach($test AS $k => $v) { 
    $lvl = explode("|", $k);
    setVal($output,$lvl,$v); 
}

$output .