How to merge subarray in PHP most easily?

Question

$arr[] = array(\'A\',\'B\');
$arr[] = array(\'C\',\'B\');
...

I need to get the merged result of all sub array of $arr .

And f

Answer 1

array_unique(array_merge($arr[0], $arr[1]));

or for an unlimited case, I think this should work:

$result_arr = array();
foreach ($arr as $sub_arr) $result_arr = array_merge($result_arr, $sub_arr);
$result_arr = array_unique($result_arr);