PHP | Ds\Deque map() Function

The Ds\Deque::map() function is an inbuilt function in PHP which is used to return the Deque with each element modified on the basis of operation performed as per the callback function.

Syntax:

public Ds\Deque::map( $callback ) : Ds\Deque

Parameters: This function accepts single parameter $callback which contains the callable function on the operation to be performed on each element of the Deque.

Return Value: This function returns a Deque with each element modified.

Below programs illustrate the Ds\Deque::map() function in PHP:

Program 1:

<?php

// Declare a Deque
$deck = new \Ds\Deque([1, 2, 3, 4, 5, 6]);

echo("Elements of deque\n");

// Display the Elements of Deque
print_r($deck);

// Deque after mapping each value as
// per in the callable function
print_r($deck->map(function($element) {

    // performing operation on each element
    return $element * 10;
}));

?>

Output:

Elements of deque
Ds\Deque Object
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
)
Ds\Deque Object
(
    [0] => 10
    [1] => 20
    [2] => 30
    [3] => 40
    [4] => 50
    [5] => 60
)

Program 2:

<?php

// Declare a Deque
$deck = new \Ds\Deque([10, 20, 30, 40, 50, 60]);

echo("Elements of deque\n");

// Display the Elements of Deque
print_r($deck);

// Deque after mapping each value as
// per in the callable function
print_r($deck->map(function($element) {

    // performing operation on each element
    return $element / 10;
}));

?>

Output:

Elements of deque
Ds\Deque Object
(
    [0] => 10
    [1] => 20
    [2] => 30
    [3] => 40
    [4] => 50
    [5] => 60
)
Ds\Deque Object
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
)

Reference: http://php.net/manual/en/ds-deque.map.php