python写的的简单的爬虫小程序

import re 
import urllib
def getHtml(url):
    page=urllib.urlopen(url)
    html=page.read()
    return html
def getpic(html):
    s=r'src="(.*?.jpg)" pic_ext'
    reg=re.compile(s)                      #这句可有可无
    piclist=re.findall(reg,html)
    x=0
    for imgurl in piclist:
        urllib.urlretrieve(imgurl,'%d.jpg'%x)
        x=x+1
html=getHtml('http://tieba.baidu.com/p/3216903619')
getpic(html)