Question

What I want is to be able to run a function every second, irrelevant of how long the function takes (it should always be under a second). I’ve considered a number of options but not sure which is best.

If I just use the delay function it isn’t going to take into account the time the function takes to run.

If I time the function and then subtract that from a second and make up the rest in the delay it’s not going to take into account the time calculations.

I tried using threading.timer (I’m not sure about the ins and outs of how this works) but it did seem to be slower than the 1s.

Here’s the code I tried for testing threading.timer:

def update(i):
    sys.stdout.write(str(i)+'\r')
    sys.stdout.flush()
    print i
    i += 1
    threading.Timer(1, update, [i]).start()

Is there a way to do this irrelevant of the length of the time the function takes?

Answer 1

This will do it, and its accuracy won’t drift with time.

import time

start_time = time.time()
interval = 1
for i in range(20):
    time.sleep(start_time + i*interval - time.time())
    f()