Xpath安装及使用

1、xpath

1.1、xpath环境

1. 浏览器下载xpath插件
   chrome插件下载
   提取码：5iex

2. python安装lxml库

pip install lxml -i https://pypi.douban.com/simple

1.2、xpath使用

1. etree.parse() 解析本地文件
   html_tree = etree.parse(‘xxx.html’)

2. etree.HTML() 服务器响应文件
   html_tree = etree.HTML(response.read().decode(‘utf-8’))

3. html_tree.xpath(xpath路径)

4. 路径获取

   • 鼠标右键查看网页源代码
   • 快捷键 Ctrl + Shift + x 打开xpath工具
   • 在Query框输入路径,在Result中显示定位的值

1.3、xpath基本语法

1. 路径查询
   //:查询所有子孙节点,不考虑层级关系
   /:找直接子节点
2. 谓词查询
   //div[@id]
   //div[@id=“maincontent”]
3. 属性查询
   //@class
4. 模糊查询
   //div[contains(@id,“he”)]
   //div[start-with(@id,“he”)]
5. 内容查询
   //div/h1/text()
6. 逻辑运算
   //div[@id=“head” and @class=“s_down”]
   //title | //price

1.4、应用实例:爬取站长素材图片

import urllib.request
from lxml import etree

def create_request(page):
   if (page == 1):
      url = 'https://sc.chinaz.com/tupian/meinvtupian.html'
   else:
      url = 'https://sc.chinaz.com/tupian/meinvtupian_' + str(page) + '.html'
   headers = {
      'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36'
   }
   request = urllib.request.Request(url=url,headers=headers)
   return request

def get_content(request):
   response = urllib.request.urlopen(request)
   content = response.read().decode('utf-8')
   return content

def down_load(content):
   # 解析网页源码
   tree = etree.HTML(content)
   name_list = tree.xpath('//div[@id="container"]//a/img/@alt')
   src_list = tree.xpath('//div[@id="container"]//a/img/@src')
   
   # 下载图片到本地
   for i in range(len(name_list)):
      name = name_list[i]
       src = src_list[i]
       url = 'https:' + src
       urllib.request.urlretrieve(url=url,filename='./images/'+name+'.jpg')

if __name__ == '__main__':
   start_page = int(input("请输入起始页码:"))
   end_page = int(input("请输入结束页码:"))
   for page in range(start_page, end_page + 1):
        request = create_request(page)
        content = get_content(request)
        down_load(content)

2、jsonpath

文章推荐：https://blog.csdn.net/luxideyao/article/details/77802389

3、bs4

无