python提取页面内的url列表

from bs4 import BeautifulSoup  import time,re,urllib2     t=time.time()     websiteurls={}     def scanpage(url):             websiteurl=url      t=time.time()      n=0      html=urllib2.urlopen(websiteurl).read()      soup=BeautifulSoup(html)      pageurls=[]      Upageurls={}      pageurls=soup.find_all("a",href=True)         for links in pageurls:          if websiteurl in links.get("href") and links.get("href") not in Upageurls and links.get("href") not in websiteurls:              Upageurls[links.get("href")]=0      for links in Upageurls.keys():          try:              urllib2.urlopen(links).getcode()          except:              print "connect failed"          else:              t2=time.time()              Upageurls[links]=urllib2.urlopen(links).getcode()              print n,              print links,              print Upageurls[links]              t1=time.time()              print t1-t2          n+=1      print ("total is "+repr(n)+" links")      print time.time()-t        scanpage("http://news.163.com/")