Using PHP SplDoublyLinkedList

The PHP Standard PHP Library (SPL) has an implementation of a doubly linked list, which is known as SplDoublyLinkedList. If we are using the built-in class, we do not need to implement the doubly linked list ourselves. The doubly linked list implementation actually works as a stack and queue as well. The PHP implementation of the doubly linked list has lots of additional functionalities. Here are some of the common features of SplDoublyLinkedList:

Method	Description
Add	Adds a new node in a specified index
Bottom	Peeks a node from beginning of the list
Count	Returns the size of the list
Current	Returns the current node
getIteratorMode	Returns the mode of iteration
setIteratorMode	Sets the mode of iteration. For example, LIFO, FIFO, and so on
Key	Returns the current node index
next	Moves to the next node
pop	Pops a node from the end of the list
prev	Moves to the previous node
push	Adds a new node at the end of the list
rewind	Rewinds the iterator back to the top
shift	Shifts a node from...