php count duplicates in array 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: php count amount of times a value appears in array

$tmp = array_count_values($uid);
$cnt = $tmp[12];
//Or
$cnt = count(array_filter($uid,function($a) {return $a==12;}));
//In both cases $var will be a number