Python - LinkedList

linkedlist.py

# ******* Structures

class Node:
  def __init__(self, data):
    self.data = data
    self.next = None
    
    
class LinkedList:
  def __init__(self):
    self.head = None


# ******* Traversal

def __iter__(self):
  node = self.head
  while node:
    yield node
    node = node.next  

def __len__(self):
  i = 0
  for node in self:
    i += 1
  return i


# ******* Insertion
# Append
def append(self, new_node):
  if not self.head:
    self.head = new_node
    return

  for node in self:
    if not node.next:
      node.next = new_node


# Prepend
def preprend(self, new_node):
  new_node.next = self.head
  self.head = new_node
  

# Insert After Node
def insert_after(self, prev_node, new_node):
  if not prev_node:
    raise Exception('prev_node is nil')
  new_node.next = prev_node.next
  prev_node.next = new_node
  

# Insert Before Node
def insert_before(self, after_node, new_node):
  if not after_node:
    raise Exception('after_node is nil')

  if self.head is after_node:
    new_node.next = self.head
    self.head = new_node
    return

  for node in self:
    if node.next is after_node:
      self.insert_after(node, new_node)
      return

    
# ******* Deletion
def delete_node(self, key):
  if self.head and self.head.data and self.head.data == key:
    self.head = target_node.next
    return
  
  for node in self:
    if node.next and node.next.data and node.next.data == key:
      node.next = node.next.next
      return
    
  raise Exception(f'node with key {key} not found')

  
def delete_node_at_index(self, index):
  if not self.head:
    raise Exception('list is empty')
    
  if index == 0:
    self.head = self.head.next
    return
  
  i = 0
  for node in self:
    if i == index - 1:
      node.next = node.next.next
      return
    i += 1
  
  
# ******* Swap


# ******* Reversal


# ******* Merge