python中实现指定时间调用函数的方法讲解

import asyncio 
import time 
 
 
def callback(n, loop): 
 print('callback {} invoked at {}'.format(n, loop.time())) 
 
 
async def main(loop): 
 now = loop.time() 
 print('clock time: {}'.format(time.time())) 
 print('loop time: {}'.format(now)) 
 
 print('registering callbacks') 
 loop.call_at(now + 0.2, callback, 1, loop) 
 loop.call_at(now + 0.1, callback, 2, loop) 
 loop.call_soon(callback, 3, loop) 
 
 await asyncio.sleep(1) 
 
 
event_loop = asyncio.get_event_loop() 
try: 
 print('entering event loop') 
 event_loop.run_until_complete(main(event_loop)) 
finally: 
 print('closing event loop') 
 event_loop.close()

entering event loop
clock time: 1504688585.2024202
loop time: 5747.015
registering callbacks
callback 3 invoked at 5747.031
callback 2 invoked at 5747.109
callback 1 invoked at 5747.218
closing event loop