xpath基础

 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 # Author:woshinidaye
 4 
 5 #xpath是在XML文档中搜索内蒙的一门语言，html是xml的一个子集
 6 #安装lxml模块 pip install lxml
 7 
 8 
 9 from lxml import html
10 etree = html.etree
11 a = '''
12 
13     George
14     John
15     
16         abc
17         def
18         ghi
19         

20             qwe
21         
22         
23             qwe12313
24             
25                 6666
26             
27         
28     
29     Reminder
30     Don't forget the meeting!
31 
32 '''
33 
34 # tree = etree.parse('b.html')
35 tree = etree.XML(a)
36 # res = tree.xpath('/note')             #/表示层级关系，表示从根节点查找
37 # res = tree.xpath('/note/from')             #/表示层级关系
38 # res = tree.xpath('/note/from/text()')             #text()是那from下面的内容
39 # res = tree.xpath('/note/author/nick/text()')        #这样没法拿到div下的nick获取到，
40 # res = tree.xpath('/note/author/*/nick/text()')          #*可以代替author下的任何一个节点，通配符
41 # res = tree.xpath('/note/author//nick/text()')                   #//就表示所有author下的所有nick
42 # res = tree.xpath('/note/author/nick[1]/text()')         #编号从1开始！！！！[]索引
43 # res = tree.xpath(r'/note/author/nick[@id="2"]/text()')       #类似于BeautifulSoup中确定标签，这里用@id=sss来表示标签
44 res = tree.xpath('/note/author/nick/@id')               #@XXXX   获取属性值
45 for i in res:
46     print(i)
47 
48 
49 #提取页面源代码
50 #提取数据
51 '''
52 from lxml import html
53 import requests,csv
54 etree = html.etree
55 url = 'https://chengdu.zbj.com/search/f/?kw=SAAS'
56 header = {
57 "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36"
58 }
59 rep = requests.get(url=url,headers=header)
60 # print(rep.text)
61 html = etree.HTML(rep.text)   #解析
62 divs = html.xpath('/html/body/div[6]/div/div/div[2]/div[5]/div[1]/div')
63 with open('1128.txt','a+',encoding='utf-8',newline='') as f :
64     for div in divs:    #拿到每一个服务商的信息
65         service_price = div.xpath('./div/div/a[2]/div[2]/div[1]/span/text()')[0]
66         service_title = 'SAAS'.join(div.xpath('./div/div/a[2]/div[2]/div[2]/p/text()'))         #拼接
67         company = div.xpath('./div/div/a[1]/div[1]/p/text()')[1].strip()
68         a = [company,service_title,service_price]
69         csvwriter = csv.writer(f)
70         csvwriter.writerow(a)
71 print('done!!')
72 '''