How to remove duplicate values from array - php - php

Question

I am trying to remove duplicate and empty values from array with array_unique() function, but getting wrong output.
Data:
Array (
[0] => Array (
[0] =>
[1] => 1
[2] =>
[3] => 108
[4] =>
)
[1] => Array (
[0] =>
[1] => 1
[2] =>
[3] => 108
[4] =>
[5] => 101
)
[2] => Array (
[0] =>
[1] =>
[2] => 108
[3] =>
)
)
PHP:
$array = array_filter($userids);
$arrays = array_unique($array, SORT_REGULAR);
print_r($arrays);
nothing happens with SORT_REGULAR - output comes same as raw data, and without SORT_REGULAR this output is coming:
$array = array_filter($userids);
$arrays = array_unique($array);
print_r($arrays);
output:
Array (
[0] => Array
(
[0] =>
[1] => 1
[2] =>
[3] => 108
[4] =>
)
)
output I am looking for:
Array (
[0] => Array
(
[0] => 1
[1] => 108
[2] => 101
)
)

Answer 1

Those array functions only works on a single level. If you flatten the array (adding all elements in a single element array), it should be pretty straight forward.
Flatten the array
$array = array_merge(...$array);
Note: This method works fine for flattening indexed arrays like in your example, but not for associative arrays where any of the sub arrays contains the same keys.
Then filter out all empty
$array = array_filter($array);
and then remove all duplicates
$array = array_unique($array);
Or as a one-liner:
$array = array_unique(array_filter(array_merge(...$array)));
Demo: https://3v4l.org/pEJAJ