你如何在 Python 中的某个时间启动一个函数？

Question

I have a list of timestamps, and I need to call a specific method when those timestamps are reached. Those timestamps are roughly 20ms apart.

At the moment I am using busy waiting in a separate thread, but I am worried about the CPU overload. Example :

while True:
  if myTimestamp > time.time():
    mymethod()

or

while myTimestamp < time.time():
   time.sleep(0.1)
mymethod()

Is there a more efficient way to do it ? Thanks

Answer 1

There are several ways -- some are more easily portable to different operating systems than others.

Generally, what you could do is:

1. spawn a new thread for every task
2. in each thread, get the current time, and time.sleep() for the remaining time

That works, but it's not extremely accurate. You can make your life a little easier by using the sched module that comes with python (it basically does what I describe above, but might be a bit more clever).

If you need microsecond accuracy ("hard" real time constraints), python is not the tool of choice.