PHP | Ds\Deque apply() Function

The Ds\Deque::apply() function is an inbuilt function in PHP which is used to update the values of Deque by performing operations as defined by the callback function. Syntax:

public Ds\Deque::apply( $callback ) : void

Parameters: This function accepts single parameter $callback which holds the function define the operation to be performed on each element of the Deque. Return value: This function does not return any value. Below programs illustrate the Ds\Deque::apply() function in PHP: Program 1: PHP

<?php

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

echo("\nElements in the deque are\n");

// Display the deque elements
print_r($deck);

// Use apply() function to implement
// the operation
$deck->apply(function($element) { 
    return $element * 10; 
});

echo("\nUpdated elements in the deque\n");

// Display the deque elements
print_r($deck);

?> 

Program 2: PHP

<?php

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

echo("\nElements in the deque are\n");

// Display the deque elements
print_r($deck);

// Use apply() function to implement
// the operation
$deck->apply(function($element) { 
    return $element % 10; 
});

echo("\nUpdated elements in the deque\n");

// Display the deque elements
print_r($deck);

?> 

Reference: https://www.php.net/manual/en/ds-deque.apply.php