Python Multithreading/Multiprocessing Examples

--D. Thiebaut (talk) 15:27, 25 January 2017 (EST)

---

Multithreading in Python

Warning! The multithreading module in Python does not provide true parallelism. Read up on the Global Interactive Lock if you want to learn more about this problem.

Example 1

# PythonThreading_Example1.py
# D. Thiebaut
# Taken and adapted from
# https://pymotw.com/2/threading/
#
# Python program illustrating how threads can
# be created and started in Python

from __future__ import print_function
import threading
import time


def worker( Id ):
    """
    thread worker function.  It receives an Id,
    and prints a message indicating it's starting.
    waits 0.5 seconds, prints another message, and dies.
    """
    print( 'Worker %d started\n' % Id )
    time.sleep( 0.5 )
    print( 'Worker %d finished\n' % Id )
    return

def main():
    """
    Spawns 5 threads that will run the worker function.
    Waits for the threads to finish, then stops.
    """
    threads = []
    for i in range(5):
        t = threading.Thread( target=worker, args=(i,) )
        threads.append(t)
        t.start()
    print( "Main has spawn all the threads" )

    # wait for all the threads to finish
    for t in threads:
        t.join()
        
    print( "Done!" )
    
main()