Python 正则 爬新浪新闻

import urllib.request
import re
# 正则表达式
# aaaaa  aa aab aba aabb
#a(.*?)b
data = urllib.request.urlopen("http://news.sina.com.cn/").read()
data2 = data.decode("utf-8", "ignore")
pat = 'href="(http://news.sina.com.cn/.*?)"'
allurl=re.compile(pat).findall(data2)

for i in range(0,len(allurl)):
    try:
        print("第"+str(i)+"爬取")
        thisurl=allurl[i]
        file= r"D:/Python/hoilday_codes/sina/"+str(i)+".html"
        urllib.request.urlretrieve(thisurl,file)
        print("成功")
    except urllib.error.URLError as e:
        if hasattr(e, "code"):
            print(e.code)
        if hasattr(e, "reason"):
            print(e.reason)