# Python - Insert a new node at the end of the Circular Singly Linked List

In this method, a new node is inserted at the end of the circular singly linked list. For example - if the given List is 10->20->30 and a new element 100 is added at the end, the List becomes 10->20->30->100.

Inserting a new node at the end of the circular singly 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 and head 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 list is empty or not, # if empty make the new node as head if(self.head == None): self.head = newNode newNode.next = self.head return else: #5. Else, traverse to the last node temp = self.head while(temp.next != self.head): temp = temp.next #6. Adjust the links temp.next = newNode newNode.next = self.head

The below is a complete program that uses above discussed concept to insert new node at the end of the circular singly 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 newNode.next = self.head return else: temp = self.head while(temp.next != self.head): temp = temp.next temp.next = newNode newNode.next = self.head #display the content of the list def PrintList(self): temp = self.head if(temp != None): print("The list contains:", end=" ") while (True): print(temp.data, end=" ") temp = temp.next if(temp == self.head): break print() else: print("The 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