Find duplicate values in array 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: check duplicate data in array php

$counts = array_count_values($array);
            $duplicate_title  = array_filter($array, function ($value) use ($counts) {
                return $counts[$value] > 1;
            });

Example 3: php get keys of duplicate values in array

<?php
/** 
	Examples of these functions:
	array_unique, 
    array_diff_assoc, 
    array_diff, 
    array_keys, 
    array_intersect 
    
    Examle with an array: 
*/
$array = array('a', 'a', 'b', 'c', 'd');

// Unique values
$unique = array_unique($array);

// Duplicates
$duplicates = array_diff_assoc($array, $unique);

// Unique values
$result = array_diff($unique, $duplicates);

// Get the unique keys
$unique_keys = array_keys($result);

// Get duplicate keys
$duplicate_keys = array_keys(array_intersect($array, $duplicates));

Example 4: php check for duplicates in array

function has_dupes($array) {
    $dupe_array = array();
    foreach ($array as $val) {
        if (++$dupe_array[$val] > 1) {
            return true;
        }
    }
    return false;
}