Python---事件Event

Event用法：

event=threading.Event() #设置一个事件实例

event.set() #设置标志位

event.clear() #清空标志位

event.wait()  #等待设置标志位

红绿灯实例：

#红绿灯
'''标志位设定，代表绿灯，直接通行；标志位被清空，代表红灯；wait()等待变绿灯'''

import threading,time

event=threading.Event()

def lighter():
    '''0为绿灯，5为红灯，count>10重置标志位'''
    event.set()     #
    count=0
    while True:
        if count>5 and count<10:
            event.clear()
            print("\033[1;41m red light is on \033[0m")
        elif count>10:
            event.set()
            count=0
        else:
            print("\033[1;42m green light is on \033[0m")
        time.sleep(1)
        count+=1

def car(name):
    '''红灯停，绿灯行'''
    while True:
        if event.is_set():
            print("[%s] is running..."%name)
            time.sleep(0.25)
        else:
            print("[%s] sees red light,need to wait three seconds"%name)
            event.wait()
            print("\033[1;34;40m green light is on,[%s]start going \033[0m"%name)

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

car1=threading.Thread(target=car,args=("Xiaoxiong",))
car1.start()

注：车辆检测红绿灯状况的时间与通过改变count计数来改变红绿灯的每次count增加的时间可以随意设定。