import time

def consumer():

    while True:

        x = yield

        time.sleep(1)

        print('处理了数据 :',x)

def producer():
　　# 创建一个生成器对象

    c = consumer()
　　# 激活这个生成器

    next(c)

    for i in range(10):

        time.sleep(1)

        print('生产了数据 :',i)

        c.send(i)

producer()

真正的协程模块就是使用greenlet完成的切换

from greenlet import greenlet

def eat():

    print('eating start')

    g2.switch()

    print('eating end')

    g2.switch()

def play():

    print('playing start')

    g1.switch()

    print('playing end')

g1 = greenlet(eat)

g2 = greenlet(play)

g1.switch()

from gevent import monkey;monkey.patch_all()

import time

import gevent

import threading

def eat():

    print(threading.current_thread().getName())

    print(threading.current_thread())

    print('eating start')

    time.sleep(1)

    print('eating end')

def play():

    print(threading.current_thread().getName())

    print(threading.current_thread())

    print('playing start')

    time.sleep(1)

    print('playing end')

g1 = gevent.spawn(eat)

g2 = gevent.spawn(play)

g1.join()

g2.join()

进程和线程的任务切换由操作系统完成

协程任务之间的切换由程序(代码)完成,只有遇到协程模块能识别的IO操作的时候,程序才会进行任务切换,实现并发的效果

同步 和 异步

from gevent import monkey;monkey.patch_all()

import time

import gevent

def task(n):

    time.sleep(1)

    print(n)

def sync():

    for i in range(10):

        task(i)

def async():

    g_lst = []

    for i in range(10):

        g = gevent.spawn(task,i)

        g_lst.append(g)

    gevent.joinall(g_lst)  # for g in g_lst:g.join()

sync()

async()