'ValueError can only parse strings python'

Question

我正在尝试使用xpath收集一堆链接，这些链接需要从下一页抓取，但是，我一直得到的错误是只能解析字符串？我试着看一下lk的类型，在我铸造之后它是一根弦？怎么了？在

 def unicode_to_string(types):
   try:
      types = unicodedata.normalize("NFKD", types).encode('ascii', 'ignore')
      return types
  except:
      return types

def getData():
  req = "http://analytical360.com/access-points"
  page = urllib2.urlopen(req)
  tree = etree.HTML(page.read())  
  i = 0
   for lk in tree.xpath('//a[@class="sabai-file sabai-file-image sabai-file-type-jpg "]//@href'):
      print "Scraping Vendor #" + str(i)
      trees = etree.HTML(urllib2.urlopen(unicode_to_string(lk))) 
      for ll in trees.xpath('//table[@id="archived"]//tr//td//a//@href'):
         final = etree.HTML(urllib2.urlopen(unicode_to_string(ll)))

Answer 1

您应该传入字符串，而不是urllib2.orlopen。在

或许可以这样更改代码：

trees = etree.HTML(urllib2.urlopen(unicode_to_string(lk)).read()) 
    for i, ll in enumerate(trees.xpath('//table[@id="archived"]//tr//td//a//@href')):
        final = etree.HTML(urllib2.urlopen(unicode_to_string(ll)).read())

而且，您似乎没有增加i。在