Despite PHP's amazing assortment of array functions and juggling maneuvers, I found myself needing a way to get the FULL array key mapping to a specific value. This function does that, and returns an array of the appropriate keys to get to said (first) value occurrence.
function array_recursive_search_key_map($needle, $haystack) {
foreach($haystack as $first_level_key=>$value) {
if ($needle === $value) {
return array($first_level_key);
} elseif (is_array($value)) {
$callback = array_recursive_search_key_map($needle, $value);
if ($callback) {
return array_merge(array($first_level_key), $callback);
}
}
}
return false;
}
usage example:
-------------------
$nested_array = $sample_array = array(
'a' => array(
'one' => array ('aaa' => 'apple', 'bbb' => 'berry', 'ccc' => 'cantalope'),
'two' => array ('ddd' => 'dog', 'eee' => 'elephant', 'fff' => 'fox')
),
'b' => array(
'three' => array ('ggg' => 'glad', 'hhh' => 'happy', 'iii' => 'insane'),
'four' => array ('jjj' => 'jim', 'kkk' => 'kim', 'lll' => 'liam')
),
'c' => array(
'five' => array ('mmm' => 'mow', 'nnn' => 'no', 'ooo' => 'ohh'),
'six' => array ('ppp' => 'pidgeon', 'qqq' => 'quail', 'rrr' => 'rooster')
)
);
$search_value = 'insane';
$array_keymap = array_recursive_search_key_map($search_value, $nested_array);
var_dump($array_keymap);
// Outputs:
// array(3) {
// [0]=>
// string(1) "b"
// [1]=>
// string(5) "three"
// [2]=>
// string(3) "iii"
//}
----------------------------------------------
But again, with the above solution, PHP again falls short on how to dynamically access a specific element's value within the nested array. For that, I wrote a 2nd function to pull the value that was mapped above.
function array_get_nested_value($keymap, $array)
{
$nest_depth = sizeof($keymap);
$value = $array;
for ($i = 0; $i < $nest_depth; $i++) {
$value = $value[$keymap[$i]];
}
return $value;
}
usage example:
-------------------
echo array_get_nested_value($array_keymap, $nested_array); // insane
