PHP - UNSET Elements in a Deep Mixed Index/Associative Array - php

Question

I have a mixed index/associative array in PHP that can, in theory, be infinitely deep because some elements may have 'children' arrays. I attach a slimmed down example. The php array is derived from some JSON data.
I want to search on a given key/value pair and to delete any elements matching that pair at the index level.
So for example, in the array below, I wish to search for the key of 'formId' and a value of '44' and to delete elements such that $array[0][0][0][0] and $array[0][1] are removed. Obviously I will then need to re-number the array.
I need to be able to search on any key/value pair... only one pair at a time is necessary... that is to say that the above example of 'formId' of '44' might be 'viewId' of '16' next time.
I have tried numerous ways to do this, with iterators, recursive foreach loops, &$reference keys but I just cannot seem to get it right.
Array
(
[0] => Array
(
[formId] => 0
[subId] => 0
[viewId] => 0
[id] => 0
[children] => Array
(
[0] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 16
[id] => _st_node_5328_0_0
[children] => Array
(
[0] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 16
[id] => _st_node_3838_0_0_0
[children] => Array
(
[0] => Array
(
[formId] => 44
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_0
)
[1] => Array
(
[formId] => 7
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_1
)
[2] => Array
(
[formId] => 3
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_2
)
[3] => Array
(
[formId] => 10
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_3
)
[4] => Array
(
[formId] => 9
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_4
)
[5] => Array
(
[formId] => 8
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_5
)
[6] => Array
(
[formId] => 6
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_6
)
[7] => Array
(
[formId] => 5
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_7
)
[8] => Array
(
[relId] => 167
[formId] => 4
[text] => Laptop Computers
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_8
[isActive] =>
)
[9] => Array
(
[formId] => 1
[subId] =>
[viewId] => 16
[id] => _st_node_947_0_0_0_9
)
)
)
[1] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 1
[id] => _st_node_3838_0_0_1
)
[2] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 11
[id] => _st_node_3838_0_0_2
)
[3] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 12
[id] => _st_node_3838_0_0_3
)
[4] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 13
[id] => _st_node_3838_0_0_4
)
[5] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 14
[id] => _st_node_3838_0_0_5
)
[6] => Array
(
[formId] => 1
[subId] => 0
[viewId] => 110
[id] => _st_node_3838_0_0_6
)
)
)
[1] => Array
(
[formId] => 44
[subId] => 0
[viewId] => 144
[id] => _st_node_5328_0_1
)
[2] => Array
(
[formId] => 10
[subId] => 0
[viewId] => 26
[id] => _st_node_5328_0_2
)
[3] => Array
(
[formId] => 9
[subId] => 0
[viewId] => 9
[id] => _st_node_5328_0_3
)
[4] => Array
(
[formId] => 8
[subId] => 0
[viewId] => 8
[id] => _st_node_5328_0_4
)
[5] => Array
(
[formId] => 7
[subId] => 0
[viewId] => 25
[id] => _st_node_5328_0_5
)
[6] => Array
(
[formId] => 6
[subId] => 0
[viewId] => 6
[id] => _st_node_5328_0_6
)
[7] => Array
(
[formId] => 5
[subId] => 0
[viewId] => 5
[id] => _st_node_5328_0_7
)
[8] => Array
(
[formId] => 4
[subId] => 0
[viewId] => 4
[id] => _st_node_5328_0_8
)
[9] => Array
(
[formId] => 3
[subId] => 0
[viewId] => 3
[id] => _st_node_5328_0_9
)
)
)
)

Answer 1

The idea
Since you want to unset elements, you definitely want to pass the $array into the function as a reference (&$array).
You want to use recursion to allow you to dig as deep as necessary based on the actual array.
You loop over all elements of the array and the first thing you do is check whether an element is an array. If it is, you check if that subarray matches your criteria. If it does, you remove it. If it doesn't you invoke the function with the same $key, $value pair on that subarray.
The code
function removeMatching($key, $value, &$arr) {
// Iterate over all $arr elements
foreach ($arr as $i => $subarr) {
// Skip all elements that are not arrays
if (is_array($subarr)) {
// Check if the sub-array matches the criteria
if (isset($subarr[$key]) && $subarr[$key] === $value) {
// Remove it from the main array if it does
unset($arr[$i]);
} else {
// If the sub-array didn't match the criteria
// Check if it contains any other matching sub-arrays
removeMatching($key, $value, $arr[$i]);
}
}
}
}
Apply like this:
$array = []; // your array
removeMatching('formId', 44, $array);
var_dump($array);