求教：python提取页面中指定的url

#! /usr/bin/env python

#coding=utf-8

from sgmllib import SGMLParser

import urllib,re



class UrlList(SGMLParser):

    def reset(self):

        self.urls=[]

        SGMLParser.reset(self)

    def start_a(self,attrs):

        href=[v for k,v in attrs if k=='href']

        if href:

            self.urls.extend(href)

def getUrls(url):

    try:

        usock=urllib.urlopen(url)

    except:

        print "get url except"+url

        return []

    result=[]

    parser=UrlList()

    parser.feed(usock.read())

    usock.close()

    parser.close()

    urls=parser.urls

    for url in urls:

        if len(re.findall(r'^http://',url))>0:  #指定正则表达式

            result.append(url)

    return result



def spider(startURL,depth):

    f=open("D:\\url.txt","w")

    if depth<0:

        return

    else:

        urls=getUrls(startURL)

        for url in urls:

            spider(url,depth-1)

            f.write(url+"\n")

    

if __name__=="__main__":

    spider("http://www.pcuseman.com/?p=102",0)  #指定需处理网页

import urllib2

url = 'http://www.baidu.com'

request = urllib2.Request(url)

response = urllib2.urlopen(request)

page = response.read()

import re

rc = '<a href="(\S*?)" target="_blank">京ICP证030173号</a>'

re.findall(rc,page)