how to duplicate array values php code example

Example 1: get duplicate value from array php

$arr = array(1, 4, 6, 1, 8, 9, 4, 6);

$unique = array_unique($arr);

$duplicates = array_diff_assoc($arr, $unique);

print_r($duplicates);
Array ( [3] => 1 [6] => 4 [7] => 6 )

Example 2: remove duplicate values in array php

<?php
$list_programming_language = array('C#',  'C++', 'PHP', 'C#', 'PHP');
$result = array_unique($list_programming_language);
print_r($result);
?>
  
// ==> 'C#',  'C++', 'PHP'