#Implementing queue in python how to
#Implementing queue in python code

The key to optimization in head/tail keeping is to avoid requirement for getting through the whole list to perform push/pop. You implementation of queue is quite inefficient, as it has to traverse through every element of linked list. I hope it will be helpful, even though I personally believe after fixes and making sure it can work somehow you'll think about answer and start over from scratch.

#Implementing queue in python code

I'm just pointing out what you missed in your code - as you asked. Probably you wanted to use nodetodel intead. The queue.Queue implementation in the Python standard library is synchronized and provides locking semantics to support multiple concurrent producers and consumers. self.cur_node=prevnodeĬur_node is useless as member variable, you don't use it in any condition, local variable will do this work easily and you already have one (prevnode) print(node.data)īy the time of execution of these 2 lines you already have node=None and it's the cause of program crash. In simple words, Stack is a linear collection of items. For implementation, we will define a queue class which will have a list to contain the elements and a queueLength field to contain the length of the list.

#Implementing queue in python how to

Stacks is one of the earliest data structures defined in computer science. How to implement queue in python Queue is a linear data structure in which we can only access or remove the element which was added first to it. The variable head points to the first element in the linked list while last points to the last. You should set prevnode before changing node, not after. The queue.LifoQueue Class What is Stack in Data Structures Data structures are the key to organize storage in computers so that we can efficiently access and edit data. Create a class Queue with instance variables head and last. #set it to head and change current head to nextĭef dequeue(self): # A Queue IMPLEMENTS ITS STRUCTURE AS FIFO ( First IN First OUT)Įlse:# Remove the last item which entered first

What am I missing in the code class Queue: The code I have already done is below, but one thing am not able to figure out is how to delete the last item in the queue. import unittest class Queue: def init (self): self.queue self.size 0 self.maxSize 10 def enqueue (self, item): if self.size < self.maxSize: (item) def dequeue (self): ''' Removes an item from the front of the list.