How to Compare two multidimensional associative arrays with differen items count - php

Question

I have two multidimensional associative arrays with differen items count.
Important is that I don't know which aray will have more elements (A or B)
First array (A):
[0] => Array
(
[catID] => 65
[discount] => 10
[productID] => Array
(
[0] => 10887
[1] => 8508
[2] => 8350
)
[startDate] => 05/12/2022 12:00 am
[endDate] => 10/12/2022 12:00 am
)
[1] => Array
(
[catID] => 66
[discount] => 10
[productID] => Array
(
[0] => 13184
[1] => 10707
[2] => 8350
)
[startDate] => 10/12/2022 12:00 am
[endDate] => 15/12/2022 12:00 am
)
Second array (B):
[0] => Array
(
[catID] => 72
[discount] => 15
[productID] => Array
(
[0] => 16239
[1] => 16236
[2] => 10887
[3] => 13184
[4] => 8524
[5] => 13314
)
[startDate] => 12/12/2022 12:00 am
[endDate] => 15/12/2022 12:00 am
)
After compare these arrays (A, B) I'd like to retrive something like that:
Array A(remove productID if exists in array B):
[0] => Array
(
[catID] => 65
[discount] => 10
[productID] => Array
(
[1] => 8508
[2] => 8350
)
[startDate] => 05/12/2022 12:00 am
[endDate] => 10/12/2022 12:00 am
)
[1] => Array
(
[catID] => 66
[discount] => 10
[productID] => Array
(
[0] => 10707
)
[startDate] => 10/12/2022 12:00 am
[endDate] => 15/12/2022 12:00 am
)
Array B(no changes):
[0] => Array
(
[catID] => 72
[discount] => 15
[productID] => Array
(
[0] => 16239
[1] => 16236
[2] => 10887
[3] => 13184
[4] => 8524
[5] => 13314
)
[startDate] => 12/12/2022 12:00 am
[endDate] => 15/12/2022 12:00 am
)

Answer 1

Populate a flat "blacklist" array from your second array.
Loop over the first array's rows and filter the productId values against the blacklist array.
Code: (Demo)
$blacklist = array_merge(...array_column($b, 'productID'));
var_export(
array_map(
fn($row) => array_replace($row, ['productID' => array_values(array_diff($row['productID'], $blacklist))]),
$a
)
);
Or if you don't mind a classic foreach(), then this may be easier to read: (Demo)
$blacklist = array_merge(...array_column($b, 'productID'));
foreach ($a as &$row) {
$row['productID'] = array_values(array_diff($row['productID'], $blacklist));
}
var_export($a);