A general programming question: Is there a way to trigger a function every x seconds without remembering the last time it was triggered?

Question

Sorry if this is a basic question, but I want to have a function trigger every fixed amount of time, say 2 seconds. In general I would do something like:

lifetime = getCurrentTime
if (lifetime - lastTime > triggerTime)
    doTheThing()
    lastTime = lifetime
end

This normally works fine, but I'm working on a program where each object stores its own lifetime, and there could be hundreds of objects at once. I'm wondering if there's a way that each object wouldn't need to also remember its own lastTime -- I was thinking something with rounding or modulo, but even then you'd still need to remember how many times the function had triggered before.

I'm wondering if anyone knows of a good general way to have a trigger function every x seconds without having to remember the last time it triggered or how many times it's triggered?

Every x seconds, trigger all of them, and then you only store the time once. — user253751, Jan 19 '23 at 19:42
The most common thing here would be to use a standard feature already given by your Framework or System like a Timer or a Scheduler. — Ralf, Jan 19 '23 at 19:45
For your specific example of "every two seconds", you can do `if seconds % 2 == 0`, which does not require any sort of memory. This will work for any target interval that evenly divides into 60. — John Gordon, Jan 19 '23 at 19:45
Or with a bit more calculation, you can get seconds-past-midnight which would be good enough for almost any use case. — John Gordon, Jan 19 '23 at 21:00
It is unclear if you question is for lua or python you should tag to languages "just becuase" — Nifim, Jan 19 '23 at 23:28

score 0 · Answer 1 · edited Jan 19 '23 at 19:49

Have you tried using sched yet? Here's a task done every 5 seconds to get you started:

import sched
import time                                                                                                                                           
                                                                                                                                                             
def doTheThing(runnable_task, every):                                                                                                                        
    runnable_task.enter(every, 1, doTheThing, (runnable_task, every))                                                                                        
    print("The thing...")                                                                                                                                    
                                                                                                                                                             
                                                                                                                                                             
task = sched.scheduler(time.time, time.sleep)                                                                                                                
                                                                                                                                                             
every = 5                                                                                                                                                    
task.enter(every, 1, doTheThing, (task, every))                                                                                                              
                                                                                                                                                             
task.run()

A general programming question: Is there a way to trigger a function every x seconds without remembering the last time it was triggered?

1 Answers1