Built Doubly Linked List functionality

Author: pythonioncoder

DoublyLinkedList.py

@@ -0,0 +1,138 @@
+class Node:
+	def __init__(self, value):
+		self.value = value
+		self.next = None
+		self.prev = None
+
+
+class DoublyLinkedList:
+	def __init__(self, value):
+		new_node = Node(value)
+		self.head = new_node
+		self.tail = new_node
+		self.length = 1
+
+	def print_list(self):
+		temp = self.head
+		while temp is not None:
+			print(temp.value)
+			temp = temp.next
+
+	def append(self, value):
+		new_node = Node(value)
+		if self.head is None:
+			self.head = new_node
+			self.tail = new_node
+		else:
+			self.tail.next = new_node
+			new_node.prev = self.tail
+			self.tail = new_node
+		self.length += 1
+		return True
+
+	def pop(self):
+		if self.length == 0:
+			return None
+		temp = self.tail
+		if self.length == 1:
+			self.head = None
+			self.tail = None
+		else:
+			self.tail = temp.prev
+			self.tail.next = None
+			temp.prev = None
+		self.length -= 1
+		return temp
+
+	def prepend(self, value):
+		new_node = Node(value)
+		if self.length == 0:
+			self.head = new_node
+			self.tail = new_node
+		else:
+			new_node.next = self.head
+			self.head.prev = new_node
+			self.head = new_node
+		self.length += 1
+		return True
+
+	def pop_first(self):
+		if self.length == 0:
+			return None
+		temp = self.head
+		if self.length == 1:
+			self.head = None
+			self.tail = None
+		else:
+			self.head = temp.next
+			self.head.prev = None
+			temp.next = None
+		self.length -= 1
+		return temp
+
+	def get(self, index):
+		if index < 0 or index >= self.length:
+			return None
+		if index < self.length / 2:
+			temp = self.head
+			for _ in range(index):
+				temp = temp.next
+		else:
+			temp = self.tail
+			for _ in range((self.length - 1) - index):
+				temp = temp.prev
+		return temp
+
+	def set_value(self, index, value):
+		temp = self.get(index)
+		if temp:
+			temp.value = value
+			return True
+		return False
+
+	def insert(self, index, value):
+		if index == 0:
+			return self.prepend(value)
+		elif index == self.length:
+			return self.append(value)
+		left = self.get(index - 1)
+		if left:
+			right = left.next
+			new_node = Node(value)
+			left.next = new_node
+			new_node.prev = left
+			new_node.next = right
+			right.prev = new_node
+			self.length += 1
+			return True
+		return False
+
+	def remove(self, index):
+		if index == 0:
+			return self.pop_first()
+		elif index == self.length - 1:
+			return self.pop()
+		temp = self.get(index)
+		if temp:
+			left = temp.prev
+			right = temp.next
+			left.next = right
+			temp.prev = None
+			temp.next = None
+			right.prev = left
+			self.length -= 1
+			return temp
+		return None
+
+
+dll = DoublyLinkedList(0)
+dll.append(1)
+dll.append(2)
+dll.append(3)
+dll.append(4)
+dll.append(5)
+dll.append(6)
+dll.append(7)
+dll.append(8)
+dll.append(9)
+dll.print_list()

LinkedList.py

@@ -126,7 +126,6 @@ def reverse(self):
         temp = self.head
         self.head = self.tail
         self.tail = temp
-        right = temp.next
         left = None
         for _ in range(self.length):
             right = temp.next