Lists themselves are thread-safe. In CPython the GIL protects against concurrent accesses to them, and other implementations take care to use a fine-grained lock or a synchronized datatype for their list implementations. However, while lists themselves can’t go corrupt by attempts to concurrently access, the lists’s data is not protected. For example: L[0] += 1 … Read more
Queue.Queue and collections.deque serve different purposes. Queue.Queue is intended for allowing different threads to communicate using queued messages/data, whereas collections.deque is simply intended as a datastructure. That’s why Queue.Queue has methods like put_nowait(), get_nowait(), and join(), whereas collections.deque doesn’t. Queue.Queue isn’t intended to be used as a collection, which is why it lacks the likes … Read more
threading.get_ident() works, or threading.current_thread().ident (or threading.currentThread().ident for Python < 2.6).
A somewhat clumsy ascii-art to demonstrate the mechanism: The join() is presumably called by the main-thread. It could also be called by another thread, but would needlessly complicate the diagram. join-calling should be placed in the track of the main-thread, but to express thread-relation and keep it as simple as possible, I choose to place … Read more
Some threads do background tasks, like sending keepalive packets, or performing periodic garbage collection, or whatever. These are only useful when the main program is running, and it’s okay to kill them off once the other, non-daemon, threads have exited. Without daemon threads, you’d have to keep track of them, and tell them to exit, … Read more
You may use the signal package if you are running on UNIX: In [1]: import signal # Register an handler for the timeout In [2]: def handler(signum, frame): …: print(“Forever is over!”) …: raise Exception(“end of time”) …: # This function *may* run for an indetermined time… In [3]: def loop_forever(): …: import time …: … Read more
Since this question was asked in 2010, there has been real simplification in how to do simple multithreading with Python with map and pool. The code below comes from an article/blog post that you should definitely check out (no affiliation) – Parallelism in one line: A Better Model for Day to Day Threading Tasks. I’ll … Read more