如何在python中同时运行多个循环函数？

Question

i've been working on a project that i was assigned to do. it is about some sort of parking lot where the cars that enter, are generated automaticly (done) now, I've put them into a 'waiting list (because i have to represent them with a GUI module later) in order to later be assigned in a spot in the parking lot. and then they must get out the parking lot (also randomly)

The problem raises when I created a function that will always create cars randomly, now i cant call any other function because the first one is looping.

the question is, is there a way to call several looping functions at the same time?

Thanks

Answer 1

the question is, is there a way to call several looping functions at the same time?

This is a great question and there are several ways to do it.

Threading can let your functions run concurrently. The data flow between the threads should be managed using the Queue module :

# Inter-thread communication
wait_to_park = Queue()
wait_to_exit = Queue()

# Start the simulation
tg = threading.Thread(target=generate_cars)
tp = threading.Thread(target=park_cars)
tu = threading.Thread(target=unpark_cars)
tg.start(); tp.start(); tu.start()

# Wait for simumlation to finish
tg.join()
wait_to_park.join()
tp.join()
wait_to_exit.join()
tu.join()

Alternatively, you can use an event-loop such as the sched module to coordinate the events. Generators may help with this -- they work like functions that can be suspended and restarted.

Answer 2

maybe import random and then set up a range that you want certain events to happen?

def mainLoop():
   while True:
      x = random.randrange(1,100)
      if 0>x>10: do something()
      if 10>x>60: do somethingMoreFrequently()
      if 60>x>61: do somethingRarely()

etcetera

if you LITERALLY want to call several looping functions at the same time be prepared to learn about Threading. Threading is difficult and i never do it unless 100% necessary.

but this should be simple enough to achieve without

Answer 3

Don't have both infinitely loop, have then each do work if needed and return (or possibly yield). Then have your main event loop call both. Something like this:

def car_arrival():
    if need_to_generate_car:
        # do car generation stuff
    return

def car_departure()
   if time_for_car_to_leave:
       # do car leaving stuff
   return


def event_loop():
    while sim_running:
        car_arrival()
        car_departure()
        sleep(0.5)