大家好,又见面了,我是你们的朋友全栈君。
1 time.sleep
import time
for i in range(5):
print(i)
time.sleep(10)
2 用shed
import time
import sched
schedule = sched.scheduler ( time.time, time.sleep )
def func(string1,float1):
print(“now is”,time.time(),” | output=”,string1,float1)
print(time.time())
schedule.enter(2,0,func,(“test1”,time.time()))
schedule.enter(2,0,func,(“test1”,time.time()))
schedule.enter(3,0,func,(“test1”,time.time()))
schedule.enter(4,0,func,(“test1”,time.time()))
schedule.run()
print(time.time())
其中func中放要执行的函数,用schedule.enter加入要执行的函数,里面的第一个参数是延迟执行的时间,用sched.scheduler进行初始化
1512033155.9311035
now is 1512033157.9316308 | output= test1 1512033155.9311035
now is 1512033157.9316308 | output= test1 1512033155.9311035
now is 1512033158.9322016 | output= test1 1512033155.9311035
now is 1512033159.9316351 | output= test1 1512033155.9311035
1512033159.9316351
[Finished in 4.2s]
上面是执行结果,缺点是任务队列是阻塞型,即schedule里的任务不执行完,后面的主线程就不会执行
3 用threading里的timer,实现非阻塞型,即主线程要任务同时执行
import time
from threading import Timer
def print_time( enter_time ):
print “now is”, time.time() , “enter_the_box_time is”, enter_time
print time.time()
Timer(5, print_time, ( time.time(), )).start()
Timer(10, print_time, ( time.time(), )).start()
print time.time()
执行结果:
1512034286.9443169
1512034286.9452875
now is 1512034291.9460146 enter_the_box_time is 1512034286.9443169
now is 1512034296.9461012 enter_the_box_time is 1512034286.9452875
[Finished in 10.2s]
可看出任务和主线程是同步执行,但是后3位又稍有不同,应该是python的多线程并非真正的多线程导致
每天某个时间定时执行任务:
import datetime
import time
def doSth():
print(‘test’)
# 假装做这件事情需要一分钟
time.sleep(60)
def main(h=0, m=0):
”’h表示设定的小时,m为设定的分钟”’
while True:
# 判断是否达到设定时间,例如0:00
while True:
now = datetime.datetime.now()
# 到达设定时间,结束内循环
if now.hour==h and now.minute==m:
break
# 不到时间就等20秒之后再次检测
time.sleep(20)
# 做正事,一天做一次
doSth()
main()
4 linux用 crontab
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