In this article, we will discuss how to remove duplicate elements from an array in PHP. We can get the unique elements by using array_unique() function. This function will remove the duplicate values from the array.
Syntax:
array array_unique($array, $sort_flags)
Note: The keys of the array are preserved i.e. the keys of the not removed elements of the input array will be the same in the output array.
Parameters: This function accepts two parameters that are discussed below:
- $array: This parameter is mandatory to be supplied and it specifies the input array from which we want to remove duplicates.
- $sort_flags: It is optional parameter. This parameter may be used to modify the sorting behavior using these values:
- SORT_REGULAR: This is the default value of the parameter $sort_flags. This value tells the function to compare items normally (don’t change types).
- SORT_NUMERIC: This value tells the function to compare items numerically.
- SORT_STRING: This value tells the function to compare items as strings.
- SORT_LOCALE_STRING: This value tells the function to compare items as strings, based on the current locale.
Return Value: The array_unique() function returns the filtered array after removing all duplicates from the array.
Example: PHP program to remove duplicate values from the array.
PHP
<?php   // Input Array $a = array("red", "green", "red", "blue");   // Array after removing duplicates print_r(array_unique($a));   ?> |
Output
Array
(
[0] => red
[1] => green
[3] => blue
)
Example 2: PHP program to remove duplicate elements from an associative array.
PHP
<?php   // Input array $arr = array(       "a" => "MH",       "b" => "JK",       "c" => "JK",       "d" => "OR");   // Array after removing duplicates print_r(array_unique($arr));   ?> |
Output
Array
(
[a] => MH
[b] => JK
[d] => OR
)
