python – threading.Timer – repeat function every n seconds

python – threading.Timer – repeat function every n seconds

The best way is to start the timer thread once. Inside your timer thread youd code the following

class MyThread(Thread):
    def __init__(self, event):
        Thread.__init__(self)
        self.stopped = event

    def run(self):
        while not self.stopped.wait(0.5):
            print(my thread)
            # call a function

In the code that started the timer, you can then set the stopped event to stop the timer.

stopFlag = Event()
thread = MyThread(stopFlag)
thread.start()
# this will stop the timer
stopFlag.set()

From Equivalent of setInterval in python:

import threading

def setInterval(interval):
    def decorator(function):
        def wrapper(*args, **kwargs):
            stopped = threading.Event()

            def loop(): # executed in another thread
                while not stopped.wait(interval): # until stopped
                    function(*args, **kwargs)

            t = threading.Thread(target=loop)
            t.daemon = True # stop if the program exits
            t.start()
            return stopped
        return wrapper
    return decorator

Usage:

@setInterval(.5)
def function():
    ...

stop = function() # start timer, the first call is in .5 seconds
stop.set() # stop the loop
stop = function() # start new timer
# ...
stop.set() 

Or heres the same functionality but as a standalone function instead of a decorator:

cancel_future_calls = call_repeatedly(60, print, Hello, World)
# ...
cancel_future_calls() 

Heres how to do it without using threads.

python – threading.Timer – repeat function every n seconds

Improving a little on Hans Thens answer, we can just subclass the Timer function. The following becomes our entire repeat timer code, and it can be used as a drop-in replacement for threading.Timer with all the same arguments:

from threading import Timer

class RepeatTimer(Timer):
    def run(self):
        while not self.finished.wait(self.interval):
            self.function(*self.args, **self.kwargs)

Usage example:

def dummyfn(msg=foo):
    print(msg)

timer = RepeatTimer(1, dummyfn)
timer.start()
time.sleep(5)
timer.cancel()

produces the following output:

foo
foo
foo
foo

and

timer = RepeatTimer(1, dummyfn, args=(bar,))
timer.start()
time.sleep(5)
timer.cancel()

produces

bar
bar
bar
bar