6. Python program to delete a new node from the beginning of the doubly linked list.
In this program, we will create a doubly linked list and delete a node from the beginning of the list. If the list is empty, print the message "List is empty". If the list is not empty, we will make the head to point to the next node in the list then; we will delete the first node.
Consider the above example, new was the head of the list. Make head to point to next node in the list. Now, node 1 will become the new head of the list thus, deleting node new.
ALGORITHM:
- Define a Node class which represents a node in the list. It will have three properties: data, previous which will point to the previous node and next which will point to the next node.
- 2Define another class for creating a doubly linked list, and it has two nodes: head and tail. Initially, head and tail will point to null.
- 3deleteFromStart() will delete a node from the beginning of the list:
- It first checks whether the head is null (empty list) then, it will return from the function as there is no node present in the list.
- If the list is not empty, it will check whether the list has only one node.
- If the list has only one node, it will set both head and tail to null.
- If the list has more than one node then, the head will point to the next node in the list and delete the old head node.
a. display() will show all the nodes present in the list.
- Define a new node 'current' that will point to the head.
- Print current.data till current points to null.
- Current will point to the next node in the list in each iteration.
PROGRAM:
Output:
Deletion at beginning
Deletion in doubly linked list at the beginning is the simplest operation. We just need to copy the head pointer to pointer ptr and shift the head pointer to its next.
now make the prev of this new head node point to NULL. This will be done by using the following statements.
Now free the pointer ptr by using the free function.
Delete a node in a Doubly Linked List
Pre-requisite: Doubly Link List Set 1| Introduction and Insertion
Write a function to delete a given node in a doubly-linked list.
Original Doubly Linked List
Python program to delete a new node from the beginning of the doubly linked list
When it is required to delete a node from the beginning of a doubly linked list, a ‘Node’ class needs to be created. In this class, there are three attributes, the data that is present in the node, the access to the next node of the linked list, and the access to the previous node of the linked list.
Below is a demonstration for the same −
Deletion in Doubly Linked List at Beginning
Deletion in Doubly Linked List at Beginning with Introduction, Asymptotic Analysis, Array, Pointer, Structure, Singly Linked List, Doubly Linked List, Circular Linked List, Binary Search, Linear Search, Sorting, Bucket Sort, Comb Sort, Shell Sort, Heap Sort, Merge Sort, Selection Sort, Counting Sort, Stack, Qene, Circular Quene, Graph, Tree, B Tree, B+ Tree, Avl Tree etc.<< Back to DELETION
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