PHP Ds\Set reverse() Function

The Ds\Set::reverse() function of Ds\Set class in PHP is an inbuilt function which is used to reverse the order of elements present in the Set instance. This function reverses the Set in-place. That is, it does not uses any extra space and updates the original Set instance with reversed values.

Syntax:

void public Ds\Set::reverse ( void ) 

Parameters: This function does not accepts any parameters.

Return Value: This function does not returns any value. It reverses the order of elements in the actual Set instance.

Below programs illustrate the Ds\Set::reverse() function:

Program 1:

<?php

// Declare new Set
$set = new \Ds\Set(["10", "20", "30"]);

// Display the initial Set element
echo "Initial Set: \n";
var_dump($set);

// Reverse the set
$set->reverse();

// Print the reversed Set
echo "\nReversed Set is: \n";
var_dump($set);

?>

Output:

Initial Set: 
object(Ds\Set)#1 (3) {
  [0]=>
  string(2) "10"
  [1]=>
  string(2) "20"
  [2]=>
  string(2) "30"
}

Reversed Set is: 
object(Ds\Set)#1 (3) {
  [0]=>
  string(2) "30"
  [1]=>
  string(2) "20"
  [2]=>
  string(2) "10"
}

Program 2:

<?php

// Declare new Set
$set = new \Ds\Set(["Geeks", "for", "Keegs"]);

// Display the initial Set element
echo "Initial Set: \n";
var_dump($set);

// Reverse the set
$set->reverse();

// Print the reversed Set
echo "\nReversed Set is: \n";
var_dump($set);

?>

Output:

Initial Set: 
object(Ds\Set)#1 (3) {
  [0]=>
  string(5) "Geeks"
  [1]=>
  string(3) "for"
  [2]=>
  string(5) "Keegs"
}

Reversed Set is: 
object(Ds\Set)#1 (3) {
  [0]=>
  string(5) "Keegs"
  [1]=>
  string(3) "for"
  [2]=>
  string(5) "Geeks"
}

Reference: http://php.net/manual/en/ds-set.reverse.php