Singly Linked List with Python (Data Structure)

Singly Linked List : So In this post we're gonna talk about implementation of singly linked list using Python and also implementation of some basic operation on linked list...

• For Creating Node:

class Node:

def __init__(self, data=None):

self.data = data

self.next = None

•  From Here Linked List and Operation on linked list:

class LinkedList:

def __init__(self):

self.head = None

• Insertion on Node in Linked list: 

   - Insert At End:

def insertAtEnd(self, newdata):

NewNode = Node(newdata) # creating Node

# if linked list is empty

if self.head is None:

self.head = NewNode

return

# if not empty

cur = self.head

# to get last element's next

while cur.next:

cur = cur.next

# set last element as NewNode

cur.next = NewNode

print(newdata, " Added At the End of Linked List")

   - Insert At Beginning:

def insertAtBeginning(self,newdata):

NewNode = Node(newdata)

# Every NewNode's next will be None

# update head value of linked list

NewNode.next = self.head

self.head = NewNode

print(newdata," Added At the beginning of Linked List")

   - Insert In Between:

def insertInBetween(self,middle_node,newdata):

# newdata will be added after middle_node(first occurence of 

        middle_node.data)

if middle_node is None:

print("Middle Node is None....")

return

NewNode = Node(newdata)

NewNode.next = middle_node.next

middle_node.next = NewNode

print(newdata," Added In between ",middle_node.data," and ",

        NewNode.next.data)

•  Traversing Linked List:

 

def traverse(self,optional=None):

cur = self.head

if cur is None:

print("Linked List is Empty")

return

print("Displaying elements of Linked List")

while cur is not None:

print(cur.data, end = ' ')

cur = cur.next

print()

 

• Removing Data:

# it removes first occurrence of removedata in linked list

def removeNode(self,removedata):

cur = self.head

if cur == None:

print("Linked List is Empty")

return

if cur is not None:

if cur.data == removedata:

self.head = cur.next

cur = None

print(removedata," is removed from Linked List")

return

# ex: 1 2 3 4 5 6 where removedata = 3

prev = None

while cur:

if cur.data == removedata:

#prev.next.data = 3 replace by cur.next.data = 4

prev.next = cur.next

cur = None

print(removedata," is removed from Linked List")

return

prev = cur #cur.data = 2

cur = cur.next #cur.data = 3

print(removedata," is not in Linked List")

    

• Search Data:

def search(self, searchdata):

cur = self.head

while cur:

if cur.data == searchdata:

print(searchdata," is in Linked List")

return

cur = cur.next

print(searchdata," is not availabel in Linked List")

• Update First Occurrence:

def update(self, olddata, newdata):

cur = self.head

while cur:

if cur.data == olddata:

cur.data = newdata

print(newdata," replaced by ",olddata)

return

cur = cur.next

print(olddata," is not availabel in Linked List")

• Merge Two Linked List:

def mergeLinkedList(self,head1,head2):

if head1 is None:

return head2

if head2 is None:

return head1

while head1.next:

head1 = head1.next

head1.next = head2

 

 

Note: If there is some indentation problem while pasting code so take a look at          that problem , and If you have any better implementation then you can          comment.

      Open for suggestion

Next Post will be about sorting Algorithms of singly Linked List in Python

Thank You 😊😊

 

Sorting Algorithms:

• Bubble sort on Singly Linked List 
• Insertion sort on Singly Linked List
• Merge Sort for Singly Linked List  
• Quick Sort for Singly Linked list