python异步之async_await

import asyncio
async def f1():
     print(1)
     await asyncio.sleep(2)
     print(2)

async def f2():
     print(3)
     await asyncio.sleep(2)
     print(4)

 tasks=[
     asyncio.ensure_future(f1()),
     asyncio.ensure_future(f2())
 ]
loop=asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))
#await只能在async内部使用，但是可以在ipython中直接使用