ported linked list code

Author: bfaure

Linked_List/main.py

@@ -0,0 +1,130 @@
+
+class node:
+	def __init__(self,data=None):
+		self.data=data
+		self.next=None
+
+class linked_list:
+	def __init__(self):
+		self.head=node()
+
+	# Adds new node containing 'data' to the end of the linked list.
+	def append(self,data):
+		new_node=node(data)
+		cur=self.head
+		while cur.next!=None:
+			cur=cur.next
+		cur.next=new_node
+
+	# Returns the length (integer) of the linked list.
+	def length(self):
+		cur=self.head
+		total=0
+		while cur.next!=None:
+			total+=1
+			cur=cur.next
+		return total 
+
+	# Prints out the linked list in traditional Python list format. 
+	def display(self):
+		elems=[]
+		cur_node=self.head
+		while cur_node.next!=None:
+			cur_node=cur_node.next
+			elems.append(cur_node.data)
+		print(elems)
+
+	# Returns the value of the node at 'index'. 
+	def get(self,index):
+		if index>=self.length() or index<0: # added 'index<0' post-video
+			print("ERROR: 'Get' Index out of range!")
+			return None
+		cur_idx=0
+		cur_node=self.head
+		while True:
+			cur_node=cur_node.next
+			if cur_idx==index: return cur_node.data
+			cur_idx+=1
+
+	# Deletes the node at index 'index'.
+	def erase(self,index):
+		if index>=self.length() or index<0: # added 'index<0' post-video
+			print("ERROR: 'Erase' Index out of range!")
+			return 
+		cur_idx=0
+		cur_node=self.head
+		while True:
+			last_node=cur_node
+			cur_node=cur_node.next
+			if cur_idx==index:
+				last_node.next=cur_node.next
+				return
+			cur_idx+=1
+
+	# Allows for bracket operator syntax (i.e. a[0] to return first item).
+	def __getitem__(self,index):
+		return self.get(index)
+
+
+	#######################################################
+	# Functions added after video tutorial
+
+	# Inserts a new node at index 'index' containing data 'data'.
+	# Indices begin at 0. If the provided index is greater than or 
+	# equal to the length of the linked list the 'data' will be appended.
+	def insert(self,index,data):
+		if index>=self.length() or index<0:
+			return self.append(data)
+		cur_node=self.head
+		prior_node=self.head
+		cur_idx=0
+		while True:
+			cur_node=cur_node.next
+			if cur_idx==index: 
+				new_node=node(data)
+				prior_node.next=new_node
+				new_node.next=cur_node
+				return
+			prior_node=cur_node
+			cur_idx+=1
+
+	# Inserts the node 'node' at index 'index'. Indices begin at 0.
+	# If the 'index' is greater than or equal to the length of the linked 
+	# list the 'node' will be appended.
+	def insert_node(self,index,node):
+		if index<0:
+			print("ERROR: 'Erase' Index cannot be negative!")
+			return
+		if index>=self.length(): # append the node
+			cur_node=self.head
+			while cur_node.next!=None:
+				cur_node=cur_node.next
+			cur_node.next=node
+			return
+		cur_node=self.head
+		prior_node=self.head
+		cur_idx=0
+		while True:
+			cur_node=cur_node.next
+			if cur_idx==index: 
+				prior_node.next=node
+				return
+			prior_node=cur_node
+			cur_idx+=1
+
+	# Sets the data at index 'index' equal to 'data'.
+	# Indices begin at 0. If the 'index' is greater than or equal 
+	# to the length of the linked list a warning will be printed 
+	# to the user.
+	def set(self,index,data):
+		if index>=self.length() or index<0:
+			print("ERROR: 'Set' Index out of range!")
+			return
+		cur_node=self.head
+		cur_idx=0
+		while True:
+			cur_node=cur_node.next
+			if cur_idx==index: 
+				cur_node.data=data
+				return
+			cur_idx+=1