python多线程与单线程之间的差距

对于python多线程与单线程之间有多少差距呢?今天用一个小例子比较一下。说明:爬取代理ip网站ip并用代理ip访问某网站，看执行后的用时多少。单线程版
# -*- coding: utf-8 -*-import requestsfrom bs4 import BeautifulSoup as bsimport reimport timedef proxy_list(mbUrl):    headers={'User-Agent':"Mozilla/5.0 (Windows NT 6.3; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0"}    url='http://www.xicidaili.com/nn/'    r=requests.get(url=url,headers=headers)    soup=bs(r.content)    datas=soup.find_all(name='tr',attrs={'class':re.compile('|[^odd]')})    i = 0    for data in datas:        soup_proxy_content=bs(str(data))        soup_proxys=soup_proxy_content.find_all(name='td')        #for i in[1,2,5]:        #   print soup_proxys[i].string        ip=str(soup_proxys[1].string)        port=str(soup_proxys[2].string)        types=str(soup_proxys[5].string)        proxy_test(mbUrl,ip,port,types)        #thread.start_new_thread(proxy_test,(mbUrl,ip,port,types))def proxy_test(url,ip,port,types):    proxy={}    proxy[types.lower()]='%s:%s'%(ip,port)    #proxy={'http':'106.46.136.24:808'}    try:            r=requests.get(url,proxies=proxy,timeout=3) #会把每个代理ip都测试一遍，超时设置为六秒            ip_content=re.findall(r'\[(.*?)\]',r.text)[0]#匹配[]中的ip            #print r.text            if ip==ip_content:#判断代理是否测试成功                #lock.acquire()#线程锁                print proxy                #lock.release()    except Exception,e:        #print e        pass#测试一下if __name__=='__main__':    time_start=time.time()    #lock = thread.allocate_lock()  # 定义一个线程锁    proxy_list("http://1212.ip138.com/ic.asp")    time_finished=time.time()-time_start    print time_finished

运行结果:

{'http': '39.85.13.253:9999'}

{'http': '113.124.9.229:8998'}
{'http': '124.88.67.52:843'}
{'http': '123.132.170.185:9999'}
{'http': '123.132.179.153:9999'}
{'http': '106.46.136.145:808'}
{'http': '111.124.245.121:9999'}
{'http': '218.17.43.228:3128'}
{'http': '58.23.103.106:9999'}
{'http': '42.84.103.140:9999'}
{'http': '140.240.245.167:9999'}
{'http': '106.46.136.96:808'}

85.9160001278

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多线程版# -*- coding: utf-8 -*-import requestsfrom bs4 import BeautifulSoup as bsimport reimport threading,threadimport timedef proxy_list(mbUrl):    headers={'User-Agent':"Mozilla/5.0 (Windows NT 6.3; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0"}    url='http://www.xicidaili.com/nn/'    r=requests.get(url=url,headers=headers)    soup=bs(r.content)    datas=soup.find_all(name='tr',attrs={'class':re.compile('|[^odd]')})    datalen=len(datas)    threads=[] #定义一个线程队列    ip = []    port = []    types = []    for i in range(datalen):        soup_proxy_content=bs(str(datas[i]))        soup_proxys=soup_proxy_content.find_all(name='td')        ip.append(str(soup_proxys[1].string))        port.append(str(soup_proxys[2].string))        types.append(str(soup_proxys[5].string))    for i in range(datalen):        t=threading.Thread(target=proxy_test,args=(mbUrl,ip[i],port[i],types[i],))        threads.append(t)    for i in range(datalen):        threads[i].start()        #time.sleep(0.2)    for i in range(datalen):        threads[i].join()def proxy_test(url,ip,port,types):    proxy={}    proxy[types.lower()]='%s:%s'%(ip,port)    try:            r=requests.get(url,proxies=proxy,timeout=3) #会把每个代理ip都测试一遍，超时设置为六秒            ip_content=re.findall(r'\[(.*?)\]',r.text)[0]#匹配[]中的ip            if ip==ip_content:#判断代理是否测试成功                lock.acquire()  # 线程锁                print proxy                lock.release()    except Exception,e:        #print e        pass#测试一下if __name__=='__main__':    time_start=time.time()    lock = thread.allocate_lock()  # 定义一个线程锁    proxy_list("http://1212.ip138.com/ic.asp")    time_finished=time.time()-time_start    print time_finished运行结果:{'http': '123.132.170.185:9999'}{'http': '180.107.249.162:9999'}{'http': '110.244.202.201:9999'}{'http': '123.52.220.243:9999'}{'http': '121.31.143.237:8123'}{'http': '110.73.2.236:8123'}{'http': '106.46.136.24:808'}{'http': '110.72.41.108:8123'}{'http': '140.240.245.167:9999'}{'http': '218.17.43.228:3128'}{'http': '220.166.241.213:8118'}3.36299991608

多线程版的仅用了3.3秒，而单线程版的却用了86秒，足足差了26倍。这之间的差距一目了然。