FIFO dequeueing in python?
- by Aaron Ramsey
hello again everybody—
I'm looking to make a functional (not necessarily optimally efficient, as I'm very new to programming) FIFO queue, and am having trouble with my dequeueing.
My code looks like this:
class QueueNode:
def __init__(self, data):
self.data = data
self.next = None
def __str__(self):
return str(self.data)
class Queue:
def__init__(self):
self.front = None
self.rear = None
self.size = 0
def enqueue(self, item)
newnode = QueueNode(item)
newnode.next = None
if self.size == 0:
self.front = self.rear = newnode
else:
self.rear = newnode
self.rear.next = newnode.next
self.size = self.size+1
def dequeue(self)
dequeued = self.front.data
del self.front
self.size = self.size-1
if self.size == 0:
self.rear = None
print self.front #for testing
if I do this, and dequeue an item, I get the error "AttributeError: Queue instance has no attribute 'front'." I guess my function doesn't properly assign the new front of the queue? I'm not sure how to fix it though.
I don't really want to start from scratch, so if there's a tweak to my code that would work, I'd prefer that—I'm not trying to minimize runtime so much as just get a feel for classes and things of that nature.
Thanks in advance for any help, you guys are the best.
