How can I use threading in Python?

Question

I am trying to understand threading in Python. I\'ve looked at the documentation and examples, but quite frankly, many examples are overly sophisticated and I\'m having trou

Answer 1

I found this very useful: create as many threads as cores and let them execute a (large) number of tasks (in this case, calling a shell program):

import Queue
import threading
import multiprocessing
import subprocess

q = Queue.Queue()
for i in range(30): # Put 30 tasks in the queue
    q.put(i)

def worker():
    while True:
        item = q.get()
        # Execute a task: call a shell program and wait until it completes
        subprocess.call("echo " + str(item), shell=True)
        q.task_done()

cpus = multiprocessing.cpu_count() # Detect number of cores
print("Creating %d threads" % cpus)
for i in range(cpus):
     t = threading.Thread(target=worker)
     t.daemon = True
     t.start()

q.join() # Block until all tasks are done