Skip to content
Related Articles

Related Articles

PHP | SplDoublyLinkedList key() Function
  • Last Updated : 23 Aug, 2019
GeeksforGeeks - Summer Carnival Banner

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

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up
Recommended Articles
Page :