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Multithreaded Priority Queue in Python

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The Queue module is primarily used to manage to process large amounts of data on multiple threads. It supports the creation of a new queue object that can take a distinct number of items. The get() and put() methods are used to add or remove items from a queue respectively. Below is the list of operations that are used to manage Queue:
  • get(): It is used to add an item to a queue.
  • put(): It is used to remove an item from a queue.
  • qsize(): It is used to find the number of items in a queue.
  • empty(): It returns a boolean value depending upon whether the queue is empty or not.
  • full(): It returns a boolean value depending upon whether the queue is full or not.
A Priority Queue is an extension of the queue with the following properties:
  • An element with high priority is dequeued before an element with low priority.
  • If two elements have the same priority, they are served according to their order in the queue.
Below is a code example explaining the process of creating multi-threaded priority queue: Example:
import queue
import threading
import time
thread_exit_Flag = 0
class sample_Thread (threading.Thread):
   def __init__(self, threadID, name, q):
      self.threadID = threadID = name
      self.q = q
   def run(self):
      print ("initializing " +
      process_data(, self.q)
      print ("Exiting " +
# helper function to process data        
def process_data(threadName, q):
   while not thread_exit_Flag:
      if not workQueue.empty():
         data = q.get()
         print ("% s processing % s" % (threadName, data))
thread_list = ["Thread-1", "Thread-2", "Thread-3"]
name_list = ["A", "B", "C", "D", "E"]
queueLock = threading.Lock()
workQueue = queue.Queue(10)
threads = []
threadID = 1
# Create new threads
for thread_name in thread_list:
   thread = sample_Thread(threadID, thread_name, workQueue)
   threadID += 1
# Fill the queue
for items in name_list:
# Wait for the queue to empty
while not workQueue.empty():
# Notify threads it's time to exit
thread_exit_Flag = 1
# Wait for all threads to complete
for t in threads:
print ("Exit Main Thread")

initializing Thread-1
initializing Thread-2initializing Thread-3

Thread-2 processing AThread-3 processing B

Thread-3 processing C
Thread-3 processing D
Thread-2 processing E
Exiting Thread-2
Exiting Thread-1
Exiting Thread-3
Exit Main Thread
Note: The output may differ depending upon the device specifications and processing power.

Last Updated : 31 Dec, 2020
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