array_unique for arrays inside array

Question

I need a function like array_unique for arrays inside array.

The Case - should be equal, but output "not equal":

<?php
$arr=array(array('a',1),array('a',2));
$arr2=array_unique($arr);
if($arr2==$arr){
  echo "equal";
}
else{
  echo "not equal";
}
?>

How should the code be changed to get output "equal"?

Answer 1

You should modify your call for array_unique to have it include the SORT_REGULAR flag.

$arr2 = array_unique($arr, SORT_REGULAR);

Answer 2

If you want to test if the outer array has unique entries, then stringify the inner contents first for a comparison:

$arr1 = array_map("serialize", $arr);
$arr2 = array_unique($arr1);
if ($arr2 == $arr1) {

Answer 3

function array_unique_when_values_are_serializable($main_array) {
    return array_map('unserialize', array_values(array_unique(array_map('serialize', $main_array))));
}