XPath总是返回一个空列表

Question

Well, I don't know why the 'title_List' always return none. 好吧，我不知道为什么“ title_List”总是不返回任何内容。
I just have tried to change the "User-Agent" but the result is the same. 我只是尝试更改“用户代理”，但结果是相同的。

Can anybody tell me where is wrong with my code? 有人可以告诉我我的代码哪里出问题了吗？

And the Xpath is right by using chrome xpath-helper like following img. 通过使用chrome xpath-helper（如下面的img），Xpath是正确的。

This is my code: 这是我的代码：

#coding=utf-8
import re
import urllib2
import urllib
from lxml import etree


def init():

    url = 'https://tieba.baidu.com/f?kw=%E7%BE%8E%E5%A5%B3&ie=utf-8&pn=0'
    headers = {"User-Agent": "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_8; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50"}
    request = urllib2.Request(url, headers=headers)
    response = urllib2.urlopen(request).read()
    print(1)
    print(response)
    #shape response get data
    get_title(response)
    print(4)



#get title href
def get_title(response):
    #html->xpath
    html_dom = etree.HTML(response)

    ts = html_dom.xpath('//div[@class="threadlist_lz clearfix"]/div/a[@class="j_th_tit"]/@href')
    print(2)
    print(ts)
    for href in ts:
        full_link='https://tieba.baidu.com'+str(href)
        print(3)
        print(full_link)

Result:（i have deleted some codes because the limitation!） 结果：（由于限制我删除了一些代码！）

    1
    <!DOCTYPE html>
    <!--STATUS OK-->
    <html>
    ...
<div class="threadlist_lz clearfix">
                <div class="threadlist_title pull_left j_th_tit 
">
    <i class="icon-member-top" alt="会员置顶" title="会员置顶" ></i><i class="icon-good" alt="精品" title="精品" ></i>

    <a rel="noreferrer" href="/p/5006374769" title="【答疑解惑】误删误封绿色通道" target="_blank" class="j_th_tit ">【答疑解惑】误删误封绿色通道</a>
</div><div class="threadlist_author pull_right">

...




2
[]
4

Answer 1

The @class attribute of your XPath expression is wrong. XPath表达式的@class属性错误。 Change it to j_th_tit (with a trailing space) and it will match. 将其更改为j_th_tit （带有尾随空格），它将匹配。

//div[@class="threadlist_lz clearfix"]/div/a[@class="j_th_tit "]/@href

To avoid these errors, it's often better to use the contains(...) function like 为了避免这些错误，通常最好使用contains(...)函数，例如

//div[contains(@class,"threadlist_lz") and contains(@class, "clearfix")]/div/a[contains(@class,"j_th_tit")]/@href

This approach is less precise, but most of the time sufficient. 这种方法不太精确，但是在大多数情况下就足够了。

XPath总是返回一个空列表

问题描述

1 个解决方案

解决方案1
1 已采纳 2019-02-08 15:33:09

XPath总是返回一个空列表

问题描述

1 个解决方案

解决方案1 1 已采纳 2019-02-08 15:33:09

解决方案1
1 已采纳 2019-02-08 15:33:09