函数返回时结束循环功能-Python

Question

My question is a bit confusing so I will explain it by saying exactly what I am trying to do.

I just got a Raspberry Pi and am writing a Python project with it. I have a function that makes a light blink on and off infinitely. I want to use the blinking light to show a status of a job (one that could take awhile).

Here is the pseudo-code for what I am trying to do:

def blink():
    while 1:
        ##light on##
        time.sleep(.5)
        ##light off##
        time.sleep(.5)

longRunningJob() #stop blinking when job returns

Any ideas?

Answer 1

You may use a class to pass a stop variable and finish thread like this:

import time
from threading import Thread


class Blink(Thread):
    def __init__(self,starting_variable):
        Thread.__init__(self)
        print("starting variable: %s"%(starting_variable))
        self.stop=False

    def Stop(self):
        self.stop = True

    def blink(self):
        print("light on")
        ##light on##
        time.sleep(.5)
        print("light off")
        ##light off##
        time.sleep(.5)

    def run(self):
        while not self.stop:
            self.blink()
        print("exiting loop ...")


def longRunningJob():
    for sleep_delay in range(5):
        print("in longRunningJob with sleep: %s"%(sleep_delay))
        time.sleep(sleep_delay)


blink=Blink("something")
blink.start()

longRunningJob()

blink.Stop()
print("END")

Answer 2

Here is the solution

import threading
import time

RUNNING = False

def blink():
    while RUNNING:
        ##light on##
        time.sleep(.5)
        ##light off##
        time.sleep(.5)

t = threading.Thread(target=blink)
RUNNING = True
t.start()
longRunningJob() #stop blinking when job returns
RUNNING = False