PHP: array_unique() function

Last update on August 19 2022 21:50:40 (UTC/GMT +8 hours)

PHP: Removes duplicate values from an array

The array_unique() is used to remove duplicate values from an array.

Note: The keys are preserved. array_unique() sorts the values treated as a string at first, then will keep the first key encountered for every value, and ignore all following keys. It does not mean that the key of the first related value from the unsorted array will be kept.

Version:

(PHP 4 and above)

Syntax:

array_unique(array1, sort_flags)

Parameters:

Name	Description	Required / Optional	Type
array1	The input array.	Required	Array
sort_flags	sort_flags is used to modify the sorting behavior using following values: SORT_REGULAR - compare items normally. SORT_NUMERIC - compare items numerically SORT_STRING - compare items as strings SORT_LOCALE_STRING - compare items as strings, based on the current locale	Optional	Integer

Note: Two elements are considered equal if and only if (string) $elem1 === (string) $elem2 i.e. when the string representation is the same, the first element will be used.

Return value

The filtered array.

Value Type: Array

Example:

<?php
$fruits_list = array('Orange',  'Apple', ' Banana', 'Cherry', ' Banana');
$result = array_unique($fruits_list);
print_r($result);
?>

Output:

Array ( [0] => Orange [1] => Apple [2] => Banana [3] => Cherry )

Pictorial Presentation:

php function reference: array_unique() function

View the example in the browser

Practice here online :

See also

PHP Function Reference

Previous: array_sum
Next: array_unshift