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
The solution is to write to the file in one thread only. import Queue # or queue in Python 3 import threading class PrintThread(threading.Thread): def __init__(self, queue): threading.Thread.__init__(self) self.queue = queue def printfiles(self, p): for path, dirs, files in os.walk(p): for f in files: print(f, file=output) def run(self): while True: result = self.queue.get() self.printfiles(result) self.queue.task_done() … Read more
I don’t know if it’s the only problem with your code, but I can tell about threading — target has to be a function, instead you call functions, making them run in main thread. So if first function is an infinite loop — program will not create any threads, because it will stuck executing the … Read more
Is this saying that this program won’t ever finish? Yes, that program won’t finish, just try it out. I ask because I have a situation where in my main thread I’m calling sys.exit(), and the process just hangs and my other threads are running as I can see the log. Does this have anything to … Read more
The http.client.HTTPResponse-object you get back from urlopen() has a _io.BufferedReader-object attached, and this object cannot be pickled. pickle.dumps(urllib.request.urlopen(‘http://www.python.org’).fp) Traceback (most recent call last): … pickle.dumps(urllib.request.urlopen(‘http://www.python.org’).fp) TypeError: cannot serialize ‘_io.BufferedReader’ object multiprocessing.Pool will need to pickle (serialize) the results to send it back to the parent process and this fails here. Since dummy uses threads instead … Read more
Since there are often questions about using QThread in PyQt, similar to yours, here is an example that shows how to correctly use threads in PyQt. I’m hoping it can be useful as a goto-answer for similar questions so I spent a bit more time than usual preparing this. The example creates a number of … Read more
The args kwarg of threading.Thread expects an iterable, and each element in that iterable is being passed to the target function. Since you are providing a string for args: t = threading.Thread(target=startSuggestworker, args=(start_keyword)) each character is being passed as a separate argument to startSuggestworker. Instead, you should provide args a tuple: t = threading.Thread(target=startSuggestworker, args=(start_keyword,)) … Read more
You would call the cancel method after you start the timer: import time import threading def hello(): print “hello, world” time.sleep(2) t = threading.Timer(3.0, hello) t.start() var=”something” if var == ‘something’: t.cancel() You might consider using a while-loop on a Thread, instead of using a Timer. Here is an example appropriated from Nikolaus Gradwohl’s answer … Read more
I suggest you instantiate a Queue.Queue before starting the thread, and pass it as one of the thread’s args: before the thread finishes, it .puts the result on the queue it received as an argument. The parent can .get or .get_nowait it at will. Queues are generally the best way to arrange thread synchronization and … Read more
I did some speed tests as well, the time to set the flag and for action to be taken is pleasantly fast 0.00002 secs on a slow 2 processor Linux box. Example of thread pause test using set() and clear() events: import threading import time # This function gets called by our thread.. so it … Read more