Question

suppose I have a multidimensional array structure:

array(parent)
    array
    array
    array(parent)
        array(parent)
            ...some key I'm looking for....
        array
    array
array
array
array
array
array

I iterate over it recursively to find an array that contains some key I’m looking for – this is no problem.

But then I need to walk up the tree and add additional key to all parents (marked by parent). I can’t wrap my head around it. I can easily walk down the tree recursively but I can’t figure out how to walk up. Can someone point me to the right direction?

Answer 1

This is an example that I’ve just wrote just to get the idea.

NOTE that this will break execution on the first occurrence of the matched value.

codepad link

$arr = array(
    array('a','b','c','d'),
    array(61,62,63,64,65),
    array('e','f','g','h'),
    array(6,7,8,9),
    array(1,2,array(1,2,3,4,5,6,7,8),4,5,6,7,8),
    array('i','j','k','l','m'),
);

function array_walkup( $desired_value, array $array, array $keys=array() ) {
    if (in_array($desired_value, $array)) {
        array_push($keys, array_search($desired_value, $array));
        return $keys;
    }
    foreach($array as $key => $value) {
        if (is_array($value)) {
            $k = $keys;
            $k[] = $key;
            if ($find = array_walkup( $desired_value, $value, $k )) {
                return $find;
            }
        }
    }
    return false;
}

$keys = array_walkup(3, $arr);

echo "3 has been found in \$arr[".implode('][', $keys)."]";