Python - Insert a new node at the end of the Linked List
In this method, a new node is inserted at the end of the linked list. For example - if the given List is 10->20->30 and a new element 100 is added at the end, the Linked List becomes 10->20->30->100.
Inserting a new node at the end of the Linked List is very easy. First, a new node with given element is created. It is then added at the end of the list by linking the last node to the new node.
The function push_back is created for this purpose. It is a 6-step process.
def push_back(self, newElement): #1 & 2 & 3. allocate node, assign data element # assign null to the next of new node newNode = Node(newElement) #4. Check the Linked List is empty or not, # if empty make the new node as head if(self.head == None): self.head = newNode return else: #5. Else, traverse to the last node temp = self.head while(temp.next != None): temp = temp.next #6. Change the next of last node to new node temp.next = newNode
The below is a complete program that uses above discussed concept to insert new node at the end of the linked list.
# node structure class Node: def __init__(self, data): self.data = data self.next = None #class Linked List class LinkedList: def __init__(self): self.head = None #Add new element at the end of the list def push_back(self, newElement): newNode = Node(newElement) if(self.head == None): self.head = newNode return else: temp = self.head while(temp.next != None): temp = temp.next temp.next = newNode #display the content of the list def PrintList(self): temp = self.head if(temp != None): print("\nThe list contains:", end=" ") while (temp != None): print(temp.data, end=" ") temp = temp.next else: print("\nThe list is empty.") # test the code MyList = LinkedList() #Add three elements at the end of the list. MyList.push_back(10) MyList.push_back(20) MyList.push_back(30) MyList.PrintList()
The above code will give the following output:
The list contains: 10 20 30