Question

I have a situation where I have already obtained and manipulated SQL data into an array and into a tree. I am trying to avoid recursion at all costs because it has bitten me in the behind in the past.

I have an array of elements with Parent_IDs, and I’d like to be able to obtain a list of all of their children and subchildren. It shouldnt be nearly as complex as going the other way (from an array to a nested tree) which I got without issue using references, but for some reason I’m brain-frozen…

Any help appreciated.

I have the data in two possible formats because I have manipulated it already. Whichver is best for input can be used. this is a structure (print_r) of the two arrays I have:

Array
(
    [202735] => Array
        (
            [ID] => 202735
            [text] => aaafdf
            [Parent] => 
        )

    [202737] => Array
        (
            [ID] => 202737
            [text] => Filho 2
            [Parent] => 202735
        )

    [202733] => Array
        (
            [ID] => 202733
            [text] => Neto 1
            [Parent] => 202731
        )

    [202739] => Array
        (
            [ID] => 202739
            [text] => Neto 2
            [Parent] => 202737
        )

)

or

Array
(
    [0] => Array
        (
            [ID] => 202735
            [text] => aaafdf
            [Parent] => 
            [children] => Array
                (
                    [0] => Array
                        (
                            [ID] => 202737
                            [text] => Filho 2
                            [Parent] => 202735
                            [children] => Array
                                (
                                    [0] => Array
                                        (
                                            [ID] => 202739
                                            [text] => Neto 2
                                            [Parent] => 202737
                                        )

                                )

                        )

                )

        )

    [1] => Array
        (
            [ID] => 202733
            [text] => Neto 1
            [Parent] => 202731
        )

)

Desired output in the format:
(first level parent => all children and grandchildren)

array(202731=>array(202735));
array(202735=>array(202737,202739));

or similar… Ideally i’ll wrap this in a function like ListChildren($InitialParent), and return all children from such… invoking ListChildren(0) or (null) would list all elements and all subs…

(additional array elements can be ignored for the purpose of this exercise)

OBS: some data in the array is missing… namely the category above 202735, which would be 202731, but thats just because i limited the data I copied in… basically I can have either a flat array with parent ids, or a “tree” array with nested children as the source.

Answer 1

I ended up with this. Thanks for the help, in the end I reverted to a recursive code. I’ll monitor it for performance although I suppose just within the PHP layer it wont be an issue. I had a bad experience when I went in for maintenance on a project that had DB calls in a recursive function… as the usage grew the recursvie function usage grew exponentially and the DB calls went to 100s of thousands…

anyways:

    function __GetChildrenRec($Lista, $Categoria){
        // Return false if $initialParent doesn't exist
        if ($Categoria == 0) $Categoria = "";
        if (!isset($Lista[$Categoria])) return FALSE;

        // Loop data and assign children by reference
        foreach ($Lista as $CategAtual) {
            if ($CategAtual[Parent] == $Categoria) {
                $Filhos[] = $CategAtual[ID];
                $Filhos = array_merge((array)$Filhos,(array)self::__GetChildrenRec($Lista, $CategAtual[ID]));
            }
        }

        // Return the data
        return is_array($Filhos) ? $Filhos : array();
    }