Write a Function Remove_duplicates That Takes in a List and Removes Elements

This is a Python program to remove duplicates from a linked list.

Problem Description

The program creates a linked list and removes duplicates from it.

Problem Solution

1. Create a class Node with instance variables data and next.
2. Create a class LinkedList with instance variables head and last_node.
3. The variable head points to the first element in the linked list while last_node points to the last.
4. Define methods append, get_prev_node, remove and display.
5. The method append takes a data item as argument and appends a node with that data item to the list.
6. The method get_prev_node takes a reference node as argument and returns the previous node. It returns None when the reference node is the first node.
7. The method remove takes a node as argument and removes it from the list.
8. The method display traverses the list from the first node and prints the data of each node.
9. Define a function remove_duplicates which takes a linked list as argument and removes duplicates from it.
10. The function remove_duplicates uses two nested loops to remove duplicate nodes.
11. Create an instance of LinkedList, remove duplicate nodes and display the list.

Program/Source Code

Here is the source code of a Python program to remove duplicates from a linked list. The program output is shown below.

                  class                  Node:                  def                  __init__                  (                  self                  ,                  data):                  self.data                  =                  data                  self.next                  =                  None                  class                  LinkedList:                  def                  __init__                  (                  self                  ):                  self.head                  =                  None                  self.last_node                  =                  None                  def                  append(                  self                  ,                  data):                  if                  self.last_node                  is                  None:                  self.head                  =                  Node(data)                  self.last_node                  =                  self.head                  else:                  self.last_node.next                  =                  Node(data)                  self.last_node                  =                  self.last_node.next                  def                  get_prev_node(                  self                  ,                  ref_node):         current                  =                  self.head                  while                  (current                  and                  current.next                  !=                  ref_node):             current                  =                  current.next                  return                  current                  def                  remove(                  self                  ,                  node):         prev_node                  =                  self.get_prev_node                  (node)                  if                  prev_node                  is                  None:                  self.head                  =                  self.head.next                  else:             prev_node.next                  =                  node.next                  def                  display(                  self                  ):         current                  =                  self.head                  while                  current:                  print                  (current.data                  ,                  end                  =                  ' '                  )                  current                  =                  current.next                  def                  remove_duplicates(llist):     current1                  =                  llist.head                  while                  current1:         data                  =                  current1.data                  current2                  =                  current1.next                  while                  current2:                  if                  current2.data                  ==                  data:                 llist.remove                  (current2)                  current2                  =                  current2.next                  current1                  =                  current1.next                  a_llist                  =                  LinkedList(                  )                  data_list                  =                  input                  (                  'Please enter the elements in the linked list: '                  ).split                  (                  )                  for                  data                  in                  data_list:     a_llist.append                  (                  int                  (data)                  )                  remove_duplicates(a_llist)                  print                  (                  'The list with duplicates removed: '                  )                  a_llist.display                  (                  )                

Program Explanation

1. An instance of LinkedList is created.
2. The user is prompted to enter the data items for the list.
3. The function remove_duplicates is called to remove duplicates from the list.
4. The linked list is displayed.

Runtime Test Cases

Case 1: Please enter the elements in the linked list: 1 5 2 1 4 5 4 5 The list with duplicates removed:  1 5 2 4    Case 2: Please enter the elements in the linked list: 3 4 1 The list with duplicates removed:  3 4 1    Case 3: Please enter the elements in the linked list: 1 3 3 14 5 1 0 The list with duplicates removed:  1 3 14 5 0

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Write a Function Remove_duplicates That Takes in a List and Removes Elements

Source: https://www.sanfoundry.com/python-program-remove-duplicates-linked-list/

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