Answers for "queue python"

python get item from queue

"""put and get items from queue"""
>>> from Queue import Queue
>>> q = Queue()
>>> q.put(1)
>>> q.put(2)
>>> q.put(3)
>>> print list(q.queue)
[1, 2, 3]

>>> q.get()
1
>>> print list(q.queue)
[2, 3]

python threading queue

import threading, queue

q = queue.Queue()

def worker():
    while True:
        item = q.get()
        print(f'Working on {item}')
        print(f'Finished {item}')
        q.task_done()

# turn-on the worker thread
threading.Thread(target=worker, daemon=True).start()

# send thirty task requests to the worker
for item in range(30):
    q.put(item)
print('All task requests sentn', end='')

# block until all tasks are done
q.join()
print('All work completed')

queues in python

class Queue:
    def __init__(self, capacity):
        self.front = self.size = 0
        self.rear = capacity - 1
        self.Q = [None] * capacity
        self.capacity = capacity

    def isFull(self):
        return self.size == self.capacity

    def isEmpty(self):
        return self.size == 0

    def EnQueue(self, item):
        if self.isFull():
            print("Full")
            return

        self.rear = (self.rear + 1) % (self.capacity)
        self.Q[self.rear] = item
        self.size = self.size + 1
        print("%s enqueue to queue" %str(item))

    def DeQueue(self):
        if self.isEmpty():
            return "Empty"

        print("%s dequeued from queue" %str(self.Q[self.front]))
        self.front = (self.front + 1) % (self.capacity)
        self.size = self.size - 1

    def que_front(self):
        if self.isEmpty():
            print("The Queue is empty")


        print("Front item is ", self.Q[self.front])

    def que_rear(self):
        if self.isEmpty():
            print("Queue is Empty")

        print("The rear item is ", self.Q[self.rear])


queue = Queue(30)
queue.EnQueue(10)
queue.EnQueue(20)
queue.EnQueue(30)
queue.EnQueue(40)
queue.EnQueue(50)
queue.que_front()
print()
queue.DeQueue()
queue.que_front()
queue.que_rear()
print()
queue.DeQueue()
queue.que_front()
queue.que_rear()

python queue.priority queue

from queue import PriorityQueue

class PqElement(object):
    def __init__(self, value: int):
        self.val = value

    #Custom Compare Function (less than or equsal)
    def __lt__(self, other):
        """self < obj."""
        return self.val > other.val

    #Print each element function
    def __repr__(self):
        return f'PQE:{self.val}'

#Usage-
pq = PriorityQueue()
pq.put(PqElement(v))       #Add Item      - O(Log(n))
topValue = pq.get()        #Pop top item  - O(1)
topValue = pq.queue[0].val #Get top value - O(1)

python list as queue

# Demonstrate queue implementation using list
 
# Initializing a queue
queue = []
 
# Adding elements to the queue
queue.append('a')
queue.append('b')
print(queue)
 
# Removing elements from the queue
print("nElements dequeued from queue")
print(queue.pop(0))
print(queue.pop(0))
 
print("nQueue after removing elements")
print(queue)
 
# print(queue.pop(0)) will raise and IndexError as the queue is now empty

queue in python

#creating a queue using list

#defining a list

my_queue =[]

#inserting the items in the queue

my_queue.append(1)

my_queue.append(2)

my_queue.append(3)

my_queue.append(4)

my_queue.append(5)

print("The items in queue:")

print(my_queue)

#removing items from queue

print(my_queue.pop(0))

print(my_queue.pop(0))

print(my_queue.pop(0))

print(my_queue.pop(0))

#printing the queue after removing the elements

print("The items in queue:")

print(my_queue)