PHP | Ds\Map reverse() Function

The Ds/Map::reverse() function in PHP is used to in-place reverse the elements of a specified Map instance. That is, the function in-place reverses the order of elements present in the specified Map instance.

Syntax: 

Ds\Map public Ds\Map::reverse ( int $position ) 

Parameter: This function does not accepts any parameter.

Return value: The function does not returns any value.

Below programs illustrate the Ds/Map::reverse() function:

Program 1:  

<?php
// PHP program to illustrate reverse() function

$map = new \Ds\Map([1 => 10, 2 => 20, 3 => 30]);

// Reverse the Map
$map->reverse();

// Print the reversed Map
print_r($map);

?>

Output: 

Ds\Map Object
(
    [0] => Ds\Pair Object
        (
            [key] => 3
            [value] => 30
        )

    [1] => Ds\Pair Object
        (
            [key] => 2
            [value] => 20
        )

    [2] => Ds\Pair Object
        (
            [key] => 1
            [value] => 10
        )

)

Program 2: 

<?php
// PHP program to illustrate reverse() function

$map = new \Ds\Map(["first" => "Geeks", "second" => "for", 
            "third" => "Geeks"]);

// Reverse the Map
$map->reverse();

// Print the Map
print_r($map);

?>

Output: 

Ds\Map Object
(
    [0] => Ds\Pair Object
        (
            [key] => third
            [value] => Geeks
        )

    [1] => Ds\Pair Object
        (
            [key] => second
            [value] => for
        )

    [2] => Ds\Pair Object
        (
            [key] => first
            [value] => Geeks
        )

)

Reference: https://www.php.net/manual/en/ds-map.reverse.php