linkedlist.py

class Node:

	#creation of node
	def __init__(self,data):

		self.data = data #assign data
		self.next = None #initialize null

class LinkedList:

	#declaring next node as null
	def __init__(self):

		self.head = None

	def push(self,new_data):

		new_data = Node(new_data)
		#move the head data next to the new data
		new_data.next = self.head
		#make new data as first data
		self.head = new_data


	def append(self,new_data):

		new_data =  Node(new_data)

		# if there is no data push the data at first
		if self.head  is None:
			self.head = new_data
			return

		#traverse till last data to append the data
		last = self.head

		while(last.next):
			last = last.next
		#change the next of lastnode	
		last.next= new_data

	def insertafter(self,prev_data,new_data):

		if prev_data is None:
			print("The previous node should be in the list")
			return

		new_node = Node(new_data)
		#make previous node next element as new_node next element
		new_node.next = prev_data.next
		#make new_node next to the previous element
		prev_data.next = new_node

	def delete(self,key):

		temp = self.head

		if temp is None:

			print "There is no data in the linked list to delete"
			return

		#if head node itself holds key then delete
		if(temp is not None):
			if(temp == key) :

				self.head = temp.next
				temp = None
				return 

		while(temp is not None):

			if(temp == key):
				break
			prev = temp
			temp = temp.next

			prev.next = temp.next
			temp = None

	def printList(self):

		temp =  self.head

		while(temp):
			print temp.data
			temp = temp.next


if __name__ == '__main__' :

	list = LinkedList() #create a empty linked list

	list.append(6) #append 6->

	list.push(1) # 1->6

	list.push(2) # 2->1->6

	list.insertafter(list.head.next,8) # 2->1->8->6

	list.append(10) # 2->1->8->6->10

	list.delete(8)  # 2->1->6->10

	print 'created linked list is:'
	list.printList()