python提取页面内url列表的方法

from bs4 import BeautifulSoupimport time,re,urllib2t=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()-tscanpage("http://news.163.com/")