协程

一、yield支持下的协程

import time
def consumer(name):    #加了yield的函数叫生成器
    print('...%s要吃包子...' %name)
    while True:
        new_baozi = yield
        print('%s is eating baozi %s' %(name,new_baozi))

def producer():
    next(con)
    next(con2)
    print('包子制作中......')
    time.sleep(1)
    n = 0
    while n < 5:
        n += 1
        con.send(n)
        con2.send(n)


if __name__ == '__main__':
    con = consumer('c1')       #创建生成器对象
    con2 = consumer('c2')
    p = producer()     #执行函数

二、gevent库中greenlet支持的协程

from greenlet import  greenlet

def test1():
    print('1 2')
    gr2.switch()
    print('5 6')
    gr2.switch()

def test2():
    print('3 4')
    gr1.switch()
    print('7 8')

gr1 = greenlet(test1)     #创建greenlet对象
gr2 = greenlet(test2)
gr1.switch()     #switch开启该对象下的方法
'''通过switch实现上下文的切换'''

三、gevent库中gevent模块下的协程

from gevent import monkey
monkey.patch_all()   #最大程度监听I/O阻塞，节省时间
import gevent
def foo():
    print('Running in foo')
    gevent.sleep(1)     #模拟I/O阻塞
    print('Explicit context switch to foo again')

def bar():
    print('Explicit context to bar')
    gevent.sleep(1)
    print('Implicit context switch back to bar')

gevent.joinall([gevent.spawn(foo),
                gevent.spawn(bar)])
'''遇到I/O阻塞自动切换'''