How do threads work in Python, and what are common Python-threading specific pitfalls?

Question

I\'ve been trying to wrap my head around how threads work in Python, and it\'s hard to find good information on how they operate. I may just be missing a link or something,

Answer 1

Below is a basic threading sample. It will spawn 20 threads; each thread will output its thread number. Run it and observe the order in which they print.

import threading
class Foo (threading.Thread):
    def __init__(self,x):
        self.__x = x
        threading.Thread.__init__(self)
    def run (self):
          print str(self.__x)

for x in xrange(20):
    Foo(x).start()

As you have hinted at Python threads are implemented through time-slicing. This is how they get the "parallel" effect.

In my example my Foo class extends thread, I then implement the run method, which is where the code that you would like to run in a thread goes. To start the thread you call start() on the thread object, which will automatically invoke the run method...

Of course, this is just the very basics. You will eventually want to learn about semaphores, mutexes, and locks for thread synchronization and message passing.