Python开发:正则表达式获得URL

用正则表达式获得a标签中的链接地址

import urllib2

from BeautifulSoup import BeautifulSoup
import re

fp = urllib2.urlopen('http://www.baidu.com')
soup = BeautifulSoup(fp)
p=re.compile(r'<a.*?href=["\'](.*?)["\']+')
for m in re.findall(p,str(soup)):
    print m,'\n'