python3 異步模塊asyncio

yield方法引入，

這裏存在的問題是，若是你想建立從0到1,000,000這樣一個很大的序列，你不得不建立能容納1,000,000個整數的列表。

可是當加入了生成器以後，你能夠不用建立完整的序列，你只須要可以每次保存一個整數的內存便可。

import asyncio

@asyncio.coroutine
def countdown(number, n):
    while n > 0:
        yield from asyncio.sleep(1)
        print("T-minus", n, "({})".format(number))
        n -= 1
        if n == 10 and number=="A":
            raise ValueError

loop = asyncio.get_event_loop()

tasks = [
    asyncio.ensure_future(countdown("A", 20)),
    asyncio.ensure_future(countdown("B", 33)),
]
loop.run_until_complete(asyncio.wait(tasks))

loop.close()

 

 

看代碼

import asyncio

@asyncio.coroutine
def countdown(number, n):
    while n > 0:
        yield from asyncio.sleep(1)
        print("T-minus", n, "({})".format(number))
        n -= 1
        if n == 10 and number=="A":
            raise ValueError

loop = asyncio.get_event_loop()

tasks = [
    asyncio.ensure_future(countdown("A", 20)),
    asyncio.ensure_future(countdown("B", 33)),
]
loop.run_until_complete(asyncio.wait(tasks))

loop.close()

 

原理講的特別好

http://python.jobbole.com/86481/