PHP | SplDoublyLinkedList key() Function
The SplDoublyLinkedList::key() function is an inbuilt function in PHP which is used to return the index of the current node.
Syntax:
mixed SplDoublyLinkedList::key( void )
Parameters: This function does not accepts any parameters.
Return Value: It returns the index of current node.
Below programs illustrate the SplDoublyLinkedList::key() function in PHP:
Program 1:
<?php // Declare an empty SplDoublyLinkedList$list = new \SplDoublyLinkedList; // Use SplDoublyLinkedList::add() function to // add elements to the SplDoublyLinkedList$list->add(0, 30);$list->add(1, 20);$list->add(2, 30);$list->add(3, "Geeks");$list->add(4, 'G');$list->rewind(); // Use SplDoublyLinkedList::key() function// to get the keyvar_dump($list->key()); // Use next() function to increment// the index value$list->next(); // Use SplDoublyLinkedList::key() function// to get the keyvar_dump($list->key()); ?> |
Output:
int(0) int(1)
Program 2:
<?php // Declare an empty SplDoublyLinkedList$list = new \SplDoublyLinkedList(); // Use SplDoublyLinkedList::push() function to // add elements to the SplDoublyLinkedList$list->push(1);$list->push(2);$list->push(3);$list->push(8);$list->push(5); $list->rewind(); // Use SplDoublyLinkedList::key() function// to get the keyvar_dump($list->key()); // Use next() function to increment// the index value$list->next();$list->next();$list->next(); // Use SplDoublyLinkedList::key() function// to get the keyvar_dump($list->key()); ?> |
Output:
int(0) int(3)
Reference: https://www.php.net/manual/en/spldoublylinkedlist.key.php
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