# Python應用Asynchronous *初探異步/同步*
###### tags: `python`
Copyright 2021, [月下麒麟](https://hackmd.io/@YMont/note-catalog)

---

## Objectives
了解Python應用異步/同步的用法與行為
並做個簡單的紀錄

## Source Code

import asyncio
import time

now = lambda: time.time()

def dosomething(num):
    print('第 {} 任務，第一步'.format(num))
    time.sleep(2)
    print('第 {} 任務，第二步'.format(num))

async def dosomething2(num):
    print('第 {} 任務，第一步'.format(num))
    await asyncio.sleep(2)
    print('第 {} 任務，第二步'.format(num))

if __name__ == "__main__":
    start = now()
    tasks = [dosomething(i) for i in range(5)]
    print('TIME: ', now() - start)
    # ------------
    start = now()
    tasks = [dosomething2(i) for i in range(5)]
    asyncio.run(asyncio.wait(tasks))
    print('TIME: ', now() - start)


函式1使用一般同步的回應方式，執行需要花費10秒左右
函式2使用一般異步的回應方式，執行僅需花費2秒左右

Reference:[【Python教學】淺談 Coroutine 協程使用方法](https://www.maxlist.xyz/2020/03/29/python-coroutine/)