Method Name:
qsize
Method Signature:
qsize()
Parameters:
None
Return Value:
Approximate number of elements present in a queue.Queue instance.
Method Overview:
- The method qsize() returns the number of elements present in a queue.Queue instance.
Note:
- If the qsize() returns > 0, it is not guaranteed that the next call to the get() method will not block or will not succeed.
- If the qsize() returns < Queue.maxsize, it is not guaranteed that the next call to the put() method will not block or will not succeed.
Example:
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# Example Python program that uses Queue.qsize() method to get the approximate number of elements present in a queue.Queue instance import queue import threading import time
# Thread function def removeMessages(messagequeue): for i in range(4): time.sleep(1); messagequeue.get(time.time()); print("Message remover exiting");
# Thread function def generateMessages(messagequeue): for i in range(5): time.sleep(1); messagequeue.put(time.time()); print("Message generator exiting");
# Create a queue with a maximum capacity of 7 packets = queue.Queue(maxsize=7);
print("Current size of the Queue"); print(packets.qsize());
# Create a thread that populates the queue messageGenerator = threading.Thread(target=generateMessages, args=(packets,)); messageRemover = threading.Thread(target=removeMessages, args=(packets,));
messageGenerator.start(); messageRemover.start();
# Try adding upto maximum capacity from the for i in range(2): time.sleep(1); packets.put(time.time(), block=False);
messageGenerator.join(); messageRemover.join();
print("Current size of the Queue"); print(packets.qsize());
print("Parent thread exiting"); |
Output:
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Current size of the Queue 0 Message remover exiting Message generator exiting Current size of the Queue 3 Parent thread exiting |