A deque data structure is used to store the sequence of values in a contiguous memory buffer which grows and shrinks automatically. The deque is the abbreviation of “double-ended queue”.
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\Deque:: function()
Example: Below programs illustrate the Ds\Deque::get() fon in PHP:
PHP
<?php// Declare a deque$deck = new \Ds\Deque([10, 20, 3, 40, 50, 6]);echo("Elements in the Deque\n");// Display the Deque elementsprint_r($deck);echo("\nElement at index 2 in the deque: ");// Use get() function to find the index valuevar_dump($deck->get(2));?> |
Output:
Elements in the Deque
Ds\Deque Object
(
[0] => 10
[1] => 20
[2] => 3
[3] => 40
[4] => 50
[5] => 6
)
Element at index 2 in the deque: int(3)
The complete list of Ds\Deque functions are given below:
|
Functions |
Description |
|---|---|
| allocate() | This is used to allocate memory as specified in the argument. |
| apply() | Update the values of Deque by performing operations as defined by the callback function. |
| capacity() | Get the current capacity of the Deque. |
| clear() | Clear the Deque by removing all elements from the Deque. |
| __construct() | It is used to create a new instance. |
| copy() | Return a shallow copy of the Deque. |
| count() | Get the number of elements in the Deque. |
| filter() | Filter out the elements from the deque based on the operation defined in the callback function. |
| find() | Find the index of the element in the Deque if element found in the Deque. |
| first() | Returns the first value in the Deque if Deque is not empty. |
| get() | Return the value at the given index. |
| insert() | Insert the value at the given index in the Deque. |
| isEmpty() | Check the Deque is empty or not. |
| join() | Join all values in the Deque as a string. |
| last() | Return the last element of Deque if Deque is not empty. |
| map() | Returns the result of applying a callback to each value |
| merge() | Returns the result of adding all given values to the deque. |
| pop() | Remove the last element from Deque (if Deque is not empty) and return it. |
| push() | Add the elements to the Deque by appending an element at the end of the Deque. |
| remove() | Remove and return the index value. |
| reverse() | Reverse the elements in the Deque in place. |
| reversed() | Return the copy of Deque which contains the elements in reversed order. |
| rotate() | Rotate the elements of Deque by the given number of rotations. |
| set() | Set the value at the given index in the Deque. |
| shift() | Remove and return the first value of deque. |
| slice() | Return a sub-Deque which contains elements of the Deque within the index range. |
| sort() | Sort the Deque in place by arranging the elements in increasing order. |
| sorted() | Return a copy of Deque which contains the element in the original Deque in increasing order. |
| sum() | Return the sum of all elements present in the Deque. |
| toArray() | The elements of the array will be in the same order as they are in Deque. |
| unshift() | It is used to add the value in front of the deque. |
