title: AttributeError: 'list' object has no attribute 'extract'?
body: <p>I just want extract info from this url(<a href="http://www.tuniu.com/g3300/whole-nj-0/list-l1602-h0-i-j0_0/" rel="nofollow">http://www.tuniu.com/g3300/whole-nj-0/list-l1602-h0-i-j0_0/</a>) via xpath.
  As I run the following code ,it occur AttributeError: 'list' object has no attribute 'extract'?
  Is my module import wrong or dont match?</p>
  
  <pre><code># -*- coding: utf-8 -*-
  
  import urllib2
  import sys
  import lxml.html as HTML
  reload(sys)
  sys.setdefaultencoding("utf-8")
  
  
  class spider(object):
      def __init__(self):
          print u'开始爬取内容'
  
  def getSource(self, url):
      html = urllib2.Request(url)
      pageContent = urllib2.urlopen(html,timeout=60).read()
      return pageContent
  
  def getUrl(self, pageContent):
      htmlSource = HTML.fromstring(pageContent)
      urlInfo = htmlSource.xpath('//dd[@class="tqs"]/span/a/@href').extract()[0]
      return urlInfo
  
  
  if __name__ == "__main__":
      url = "http://www.tuniu.com/g3300/whole-nj-0/list-l1602-h0-i-j0_0/"
      tuniu = spider()
      tuniu.getUrl(url)
  </code></pre>
  
  <p>following is error! </p>
  
  <pre><code> Traceback (most recent call last):
   File "&lt;stdin&gt;", line 1, in &lt;module&gt;
   File "D:\anzhuang\Anaconda\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 682, in runfile
  execfile(filename, namespace)
   File "D:\anzhuang\Anaconda\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 71, in execfile
  exec(compile(scripttext, filename, 'exec'), glob, loc)
   File "D:/python/tuniu2/tuniu.py", line 34, in &lt;module&gt;
  tuniu.getUrl(url)
   File "D:/python/tuniu2/tuniu.py", line 27, in getUrl
  urlInfo = htmlSource.xpath('//dd[@class="tqs"]/span/a/@href').extract()[0]
   AttributeError: 'list' object has no attribute 'extract'
  </code></pre>