php. walk up multidimensional array? - php

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)."]";

Answer 2

You can use something along these lines in a class:
private $valueFound;
public function recurse($item)
{
if ($item['special_field'] === 'value you are looking for')
{
$this->valueFound = $item['other_field'];
return;
}
if (isset($item['child'])
{
recurse($item['child']);
}
// Use tail-recursion.
// You are at this point past all recursion and are heading back up the tree.
$item['field_to_set'] = $this->valueFound;
}