python 協程

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‘‘‘協成、對於非搶佔式的發送器 
1.與產生器 yleid()、儲存狀態
2.使用者態的切換、切換由使用者決定
3.協程本身是一種微線程
4.協成也是面向IO操作
5.沒有切換的消耗
6.沒有鎖的概念
‘‘‘

（1）產生器函數

def f():    print("ok")    s= yield 5    print(s)    print("ok2")    yieldgen=f()x=gen.__next__()print(x)gen.send(0)

（2）生產者消費者模型用yeild實現

import queueimport timeq=queue.Queue()def Cousumer(name):    print("準備開始吃包子>>>>>>>>")    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 +=2if __name__ == ‘__main__‘:   con1 =Cousumer("c1")   con2 = Cousumer("c2")   p = Producer("1號廚師")

（3）-------------greenlet 函數間的切換更加方便--------------------------

#通過 switch() 隨時切換from greenlet import greenletdef 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() # 動作的發起端too1()

（4）-----------------gevent介面遇到IO等待操作實現自動切換---------------------

import requests,time,geventt1=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)#比較串列# 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)

 

python 協程