协程是我们自己调度的

进程是系统调度的
协程切换很少开销

def yield_test():

    """实现协程函数"""

    while True:

        n = (yield)

        print(n)

if __name__ == "__main__":

    rest = yield_test()

    next(rest)

    rest.send("666")

    rest.send("666")

结果：

666

666

例如当我们读文件的时候，文件比较大，读的时候可能会有阻塞，这时候我们使用await方法，让loop调用其他的协程，
等到读完之后再回来执行

import asyncio

async def do_sth(x):

    """定义协程函数"""

    print("等待中{}".format(x))

    await asyncio.sleep(x)

#判断是否为协程函数

print(asyncio.iscoroutinefunction(do_sth))

coroutine = do_sth(5)

#事件循环队列

loop = asyncio.get_event_loop()

#注册任务

task = loop.create_task(coroutine)

print(task)

#等待协程任务执行结束

loop.run_until_complete(task)

print(task)

结果；

True

<Task pending coro=<do_sth() running at D:/PycharmProjects/untitled0406/test.py:4>>

等待中5

<Task finished coro=<do_sth() done, defined at D:/PycharmProjects/untitled0406/test.py:4> result=None>

创建协程函数

获取事件循环队列

将协程函数加入到事件队列形成任务

等待协程任务执行结束

import asyncio

async def compute(x,y):

    print("计算x + y => {0}+{1}".format(x,y))

    await asyncio.sleep(3)

    return x + y

async def get_sum(x,y):

    rest = await compute(x,y)

    print("{0} + {1} = {2}".format(x,y,rest))

#拿到事件循环

loop = asyncio.get_event_loop()

loop.run_until_complete(get_sum(1,2))

loop.close()

结果：

计算x + y => 1+2

1 + 2 = 3

#定义一个队列

#让两个协程来进行通信

#让其中一个协程往队列中写数据

#让另一个协程从队列中删除数据

import asyncio

import random

async def add(store,name):

    """

    写入数据到队列

    :param store: 队列的对象

    :return:

    """

    for i in range(5):

        #往队列添加数字

        num = "{0} - {1}".format(name,i)

        await asyncio.sleep(random.randint(1, 5))

        await store.put(i)

        print("{2}add one ... {0},size:{1}".format(num,store.qsize(),name))

async def reduce(store):

    """

    从队列中删除数据

    :param store:

    :return:

    """

    for i in range(10):

        rest = await store.get()

        print("reduce one ....{0},size{1}".format(rest,store.qsize()))

if __name__ == "__main__":

    #准备队列

    store = asyncio.Queue(maxsize=5)

    a1 = add(store,"a1111")

    a2 = add(store,"a2222")

    r1 = reduce(store)

    #添加事件队列

    loop = asyncio.get_event_loop()

    loop.run_until_complete(asyncio.gather(a1,a2,r1))

    loop.close()

a2222add one ... a2222 - 0,size:1

reduce one ....0,size0

a1111add one ... a1111 - 0,size:1

reduce one ....0,size0

a2222add one ... a2222 - 1,size:1

reduce one ....1,size0

a1111add one ... a1111 - 1,size:1

reduce one ....1,size0

a1111add one ... a1111 - 2,size:1

reduce one ....2,size0

a2222add one ... a2222 - 2,size:1

a1111add one ... a1111 - 3,size:2

reduce one ....2,size1

reduce one ....3,size0

a1111add one ... a1111 - 4,size:1

reduce one ....4,size0

a2222add one ... a2222 - 3,size:1

reduce one ....3,size0

a2222add one ... a2222 - 4,size:1

reduce one ....4,size0