PHP Ds\Set Functions Complete Reference
Last Updated :
12 Jul, 2025
Set is the collection of unique values. The implementation of Ds\Set is similar to the Ds\Map which creates a hash table. The values of Ds\Set are used as key and the mapped values are ignored.
Requirements: PHP 7 is required for both extension and the compatibility polyfill.
Installation: The easiest way to install data structure by using the PECL extension.
pecl install ds
Syntax:
public Ds\Set::functionName()
Example: Below programs illustrate the Ds\Set::count() function:
PHP
<?php
// Declare new Set
$set = new \Ds\Set([10, 15, 21]);
// Display the Set element
var_dump($set);
// Display count of elements
// present in the Set
echo "Count is : ";
print_r($set->count());
?>
Output:
object(Ds\Set)#1 (3) {
[0]=>
int(10)
[1]=>
int(15)
[2]=>
int(21)
}
Count is : 3
Complete list of data structure DS\Set:
Functions
| Description
|
|---|
| add() | It is used to add values to the set. |
| allocate() | Allocate memory for required capacity. |
| capacity() | Return the capacity of the set. |
| clear() | Remove all values from the set. |
| __construct() | Create new instance of set. |
| contains() | Check the given value exists in the set or not. |
| copy() | Return the copy of the set element. |
| count() | Count the number of values present in the Set. |
| diff() | Create a set that contains the elements of the first set which are not present in the second set. |
| filter() | Create new set using filter function. |
| first() | Returns the first element of the Set. |
| get() | Get a value from the Set instance. |
| intersect() | Create a new set that contains the intersection of two sets. |
| isEmpty() | Check whether a set is empty or not. |
| join() | It is used to join all values as string |
| last() | Return the last element from the Set instance. |
| merge() | Returns a set after adding all given values to the set. |
| reduce() | Set to a single value by applying operations using the callback function. |
| remove() | Remove specific values from a Set instance.. |
| reverse() | Reverse the order of elements present in the Set instance. |
| reversed() | Create a copy of the original Set with values arranged in reverse order. |
| slice() | Return the sub-set of a given range. |
| sort() | Sort the elements of a specified Set instance according to the values. |
| sorted() | Return a sorted copy of a given set. |
| sum() | Find the sum of all of the elements present in a Set. |
| toArray() | Convert the Set into an associative array. |
| union() | Create a new set that contains the union of two sets |
| xor() | Create a new set that contains the value either in the first set or second set but not both. |