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'); $list->rewind(); // Use SplDoublyLinkedList::key() function // to get the key var_dump($list->key()); // Use next() function to increment // the index value $list->next(); // Use SplDoublyLinkedList::key() function // to get the key var_dump($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); $list->rewind(); // Use SplDoublyLinkedList::key() function // to get the key var_dump($list->key()); // Use next() function to increment // the index value $list->next(); $list->next(); $list->next(); // Use SplDoublyLinkedList::key() function // to get the key var_dump($list->key()); ?> |
Output:
int(0) int(3)
Reference: https://www.php.net/manual/en/spldoublylinkedlist.key.php
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