PHP SplDoublyLinkedList key() Function Last Updated : 23 Jun, 2023 Comments Improve Suggest changes Like Article Like Report 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 <?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 <?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 Comment More infoAdvertise with us Next Article PHP SplDoublyLinkedList key() Function jit_t Follow Improve Article Tags : Web Technologies PHP PHP-function Similar Reads PHP SplDoublyLinkedList next() Function The SplDoublyLinkedList::next() function is an inbuilt function in PHP which is used to move the index into next index. Syntax: void SplDoublyLinkedList::next( void ) Parameters: This function does not accept any parameter. Return Value: It does not return any value. Below programs illustrate the Sp 1 min read PHP SplDoublyLinkedList isEmpty() Function The SplDoublyLinkedList::isEmpty() function is an inbuilt function in PHP which is used to check whether the doubly linked list is empty or not. Syntax: bool SplDoublyLinkedList::isEmpty( void ) Parameters: This function does not accepts any parameters. Return Value: This function returns True if do 1 min read PHP SplDoublyLinkedList pop() Function The SplDoublyLinkedList::pop() function is an inbuilt function in PHP which is used to pop the node from the end of the doubly linked list. Syntax: mixed SplDoublyLinkedList::pop( void ) Parameters: This function does not accept any parameters. Return Value: This function returns the value of a popp 1 min read PHP SplDoublyLinkedList top() Function The SplDoublyLinkedList::top() function is an inbuilt function in PHP which is used to return the value of last (top) node in a doubly-linked list. Syntax: mixed SplDoublyLinkedList::top( void ) Parameters: This function does not accepts any parameters. Return Value: It returns the value of last nod 1 min read PHP SplDoublyLinkedList prev() Function The SplDoublyLinkedList::prev() function is an inbuilt function in PHP which is used to move to the previous entry. Syntax: void SplDoublyLinkedList::prev( void ) Parameters: This function does not accepts any parameters. Return Value: It does not return any value. Below programs illustrate the SplD 1 min read PHP SplDoublyLinkedList push() Function The SplDoublyLinkedList::push() function is an inbuilt function in PHP which is used to push an element at the end of the doubly linked list. Syntax: void SplDoublyLinkedList::push( $value ) Parameters: This function accepts a single parameter $value which holds an element to push it at the end of d 1 min read PHP SplDoublyLinkedList offsetGet() Function The SplDoublyLinkedList::offsetGet() function is an inbuilt function in PHP which returns the value at given index. Syntax: mixed SplDoublyLinkedList::offsetGet( $index ) Parameters: This function accepts a single parameter $index which holds the index value. Return Value: It returns the value at gi 1 min read PHP SplDoublyLinkedList offsetSet() Function The SplDoublyLinkedList::offsetSet() function is an inbuilt function in PHP which is used to set the value at given index. Syntax: void SplDoublyLinkedList::offsetSet( $index, $newval ) Parameters: This function accepts two parameters as mentioned above and described below: $index: It holds the inde 2 min read PHP | SplDoublyLinkedList valid() Function The SplDoublyLinkedList::valid() function is an inbuilt function in PHP which is used to check whether the doubly linked list contains more nodes or not. Syntax: bool SplDoublyLinkedList::valid( void ) Parameters: This function does not accept any parameters. Return Value: This function returns TRUE 1 min read PHP SplDoublyLinkedList count() function The SplDoublyLinkedList::count() function is an inbuilt function in PHP which is used to count the number of elements present in a doubly linked list. Syntax: int SplDoublyLinkedList::count( void ) Parameters: It does not contain any parameter. Return Value: It returns the number of elements present 1 min read Like