Asyncio-异步IO（Python）

串行

import asyncio
import time

async def say_after(delay,what):
    await asyncio.sleep(delay)
    print(what)

async def main():
    print(f"started at {time.strftime('%X')}")
    await say_after(1,'hello') #await是等待say_after返回结果才能继续往下执行
    await say_after(2,'world')

    print(f"finished at {time.strftime('%X')}")

asyncio.run(main())

串行就是顺序执行

并行

import asyncio
import time

async def say_after(delay,what):
    await asyncio.sleep(delay)
    print(what)

async def main():
    task1=asyncio.create_task(say_after(1,'hello'))
    task2=asyncio.create_task(say_after(2,'world'))

    print(f"started at {time.strftime('%X')}")
    await task1
    await task2

    print(f"finished at {time.strftime('%X')}")

asyncio.run(main())

异步的核心是asyncio.create_task

参考资料：

https://docs.python.org/zh-cn/3.9/library/asyncio-task.html