python 协程

'''协成、对于非抢占式的调度程序 
1.与生成器 yleid()、保存状态
2.用户态的切换、切换由用户决定
3.协程本身是一种微线程
4.协成也是面向IO操作
5.没有切换的消耗
6.没有锁的概念
'''

（1）生成器函数

def f():
    print("ok")
    s= yield 5
    print(s)
    print("ok2")
    yield

gen=f()
x=gen.__next__()
print(x)
gen.send(0)

（2）生产者消费者模型用yeild实现

import queue
import time
q=queue.Queue()

def Cousumer(name):
    print("准备开始吃包子>>>>>>>>")
    while True:
        new_baozi = yield
        print("cousumer %s has eat %s baozi" %(name,new_baozi))

def Producer(name):
    r = con1.__next__()
    r = con2.__next__()
    n = 0
    while 1:
        time.sleep(1)
        print("Producer %s  is making baozi %s and %s" %(name,n,n+1))
        con1.send(n)
        con2.send(n+1)
        n +=2
if __name__ == '__main__':
   con1 =Cousumer("c1")
   con2 = Cousumer("c2")
   p = Producer("1号厨师")

（3）-------------greenlet 函数间的切换更加方便--------------------------

#通过 switch() 随时切换
from greenlet import greenlet
def too2():
    print(898)
    gr1.switch()
    print(34)
def too1():
    print(89)
    gr2.switch()
    print("7897978")
    gr2.switch()


gr1=greenlet(too1)
gr2=greenlet(too2)

# gr1.switch() # 动作的发起端
too1()

（4）-----------------gevent接口遇到IO等待操作实现自动切换---------------------

import requests,time,gevent
t1=time.time()
def f(url):
    print("GET: %s" % url)
    resp =requests.get(url)
    data=resp.text
    f= open("new.html","w",encoding="utf8")
    f.write(data)
    print("%d bytes recevied from %s" %(len(data),url))

gevent.joinall([
               gevent.spawn(f,"https://www.bilibili.com/video/av21663728/?p=325"),
               gevent.spawn(f,"http://news.baidu.com/"),
               gevent.spawn(f,"http://www.okoook.com/"),
               gevent.spawn(f,"https://www.imooc.com/"),
               gevent.spawn(f,"http://www.xiaohuar.com/"),
               gevent.spawn(f,"http://www.xiaohuar.com/hua/"),
              ])
# print(time.time()-t1)

#比较串行
# f("https://www.bilibili.com/video/av21663728/?p=325")
# f("http://news.baidu.com/")
#f("http://www.okoook.com/")
# f("https://www.imooc.com/")
# f("http://www.xiaohuar.com/")
# f("http://www.xiaohuar.com/hua/")

print(time.time()-t1)