get specific array in a multi-dimentional array on php - php

Question

I have the following structure of an array which is decoded from a JSON object. From this array result I need to fork widgets for processing. It is an unstable JSON array so the parent keys may differs in future but the widgets will not.
(
[2] => Array
(
[MA] => Array
(
[0] => Array
(
[activities] => Array
(
[0] => Array
(
[activity_id] => 3
[activity_name] => Excavation
[activity_unique_id] => EXCAV-d435
[created_date] => 2021-02-08 21:42:53
[end_date] => 2021-02-08 21:42:08
[fk_client_id] => 1
[fk_main_activity] => 3
[fk_project_id] => 2
[relation_type] => MA-A-SA-W
[start_date] => 2021-02-08 21:42:08
[widgets] => Array
(
[0] => Array
(
[activity_mapping] => STRUC-be4c
[check_box_val] => 0
[checkbox_unique_id] => EXCAV-dceae
[checkbox_widget_id] => 5
[created_date] => 2021-02-08 21:43:12
)
)
)
)
[created_date] => 2021-02-08 21:42:44
[end_date] => 2021-02-08 21:42:08
[fk_client_id] => 1
[fk_floor_ids] => 7
[fk_project_id] => 2
[main_activity_id] => 3
[main_activity_name] => Structure MA1
[main_activity_unique_id] => STRUC-be4c
[relation_type] => MA-A-SA-W
[sequence_no] => 1
[start_date] => 2021-02-08 21:42:08
[tower_ids] => 4
[widgets_ids] =>
)
...
it is a big source So I cut shorted it. From the above result set I only need to fork the following widgets object.
[widgets] => Array
(
[0] => Array
(
[activity_mapping] => STRUC-be4c
[check_box_val] => 0
[checkbox_unique_id] => EXCAV-dceae
[checkbox_widget_id] => 5
[created_date] => 2021-02-08 21:43:12
)
)
)
Thanks in advance.

Answer 1

This recursive function searches for the first occurrence of a key in a multidimensional array and returns its value.
function array_find_key(array $array, $key) {
if (array_key_exists($key, $array)) {
return [$key => $array[$key]];
} else {
foreach($array as $item) {
if (is_array($item) && $result = array_find_key($item, $key)) {
return $result;
}
}
}
}
$result = array_find_key($array, 'widgets');
fiddle

Answer 2

The answer from #id'7238 is designed to search for a qualifying value in the current level before attempting to traverse a deeper level. The nuance in my answer (which does not call array_key_exists()) is that it checks keys as it traverses a level and will go down a level as soon as a non-qualifying subarray is encountered.
While looping, if the key is found, the payload is returned (and potentially passed up the recursive stack). If a value is array type data, then the next level down is processed -- if that level contains a qualifying key, it is passed up the stack.
If there are no qualifying keys in the input array, then null will be returned.
Code: (Demo)
function searchByKey(array $array, $find) {
foreach($array as $k => $v) {
if ($k === $find) {
return [$k => $v];
}
if (is_array($v)) {
$result = searchByKey($v, $find);
if ($result) {
return $result;
}
}
}
}
var_export(searchByKey($a, 'foo'));

Answer 3

For fun, if the nesting level will be the same just with the keys being different, this will give you the widgets array:
$result = current(current(current(current(current($array)))))['widgets'];
This will give you the array under the widgets array:
$result = current(current(current(current(current(current($array)))))['widgets']);
The first example will only work if the widgets array is 5 levels deep in the array and for the second if there is only 1 array under widgets (if there are more you will get the first).