def add(self, item):
if self.head == None:
self.head = Node(item)
else:
temp = Node(item)
temp.set_next(self.head)
self.head.set_previous(temp)
self.head = temp
def append(self, item):
if self.head == None:
self.head = Node(item)
else:
current = self.head
while current.get_next() != None:
current = current.get_next()
temp = Node(item)
current.set_next(temp)
temp.set_previous(current)
def addToTail(self, value):
newNode = Node(value)
if not self.tail:
self.head = newNode
else:
self.tail.next = newNode
newNode.prev = self.tail
self.items.append(newNode)
self.tail = newNode
def addToHead(self, value):
newNode = Node(value)
if not self.head:
self.tail = newNode
else:
self.head.prev = newNode
newNode.next = self.head
self.items.insert(0, newNode)
self.head = newNode
def insert_after(self, item, x):
if self.head == None:
print("List is empty")
else:
current = self.head
found = False
while current != Nonde and not found:
if current.get_item() == x:
found = True
else:
current = current.get_next()
if found == False:
print("item is not in the list")
else:
temp = Node(item)
temp.set_next(current.get_next())
temp.set_previous(current)
if current.get_next() != None:
current.get_next().set_previous(temp)
current.set_next(temp)
def insertAtIndex(self, index, value):
if index > len(self.items) - 1:
return False
if index == 0:
return self.addToHead(value)
if index == len(self.items) - 1:
return self.addToTail(value)
new_node = Node(value)
before_node = self.items[index - 1]
after_node = self.items[index]
before_node.next = new_node
new_node.prev = before_node
after_node.prev = new_node
new_node.next = after_node
self.items.insert(index, new_node)