python threading.Event 方法使用，红绿灯功能实现

import time,threading

event = threading.Event()

def lighter():
    count =0
    event.set()#先设置红绿灯,设置一个全局变量标志位
    while True:
        if count >5 and count<10:#改成红灯
            event.clear()#把标志位清理，设置是TRUE，清空是false
            print("33[41;1mred light is on ...33[0m")
        elif count>10:
            event.set()#变绿灯
            count = 0
        else:
            print("33[42;1mgreen light is on ...33[0m")
        time.sleep(1)
        count +=1
def car(name):
    while True:
        if event.is_set():#代表绿灯
            print("[%s] running ..."%name)
            time.sleep(1)
        else:
            print("[%s] sees red light,waiting..."%name)
            event.wait()#去检测，标志位没有设置，卡在这
            print("33[34;1m[%s] green light is on ,start going ...33[0m"%name)

light = threading.Thread(target=lighter,)
light.start()

car1 = threading.Thread(target=car,args=('BMW',))
car1.start()