python中BeautifulSoup模块

BeautifulSoup模块是干嘛的？

答：通过html标签去快速匹配标签中的内容。效率相对比正则会好的多。效率跟xpath模块应该差不多。

一：解析器：

BeautifulSoup(html,"html.parser")
BeautifulSoup(html,'lxml')
BeautifulSoup(html,'xml')
BeautifulSoup(html,'html5lib')

假设要匹配a标签里的href属性：

1 html = "<a href='http://baidu.com/'>this is baidu.com</a>"
2 bs = BeautifulSoup(html,"lxml")
3 all_href = bs.find_all('a')
4 for i in all_href:
5     print i['href']

 1 #!usr/bin/env python
 2 #encding:utf-8
 3 #by i3ekr
 4 
 5 import requests
 6 from bs4 import BeautifulSoup
 7 
 8 html = """
 9 <!DOCTYPE html>
10 <html>
11 <head>
12     <title>title test demo</title>
13 </head>
14 <body>
15     <h1>this is h1</h1>
16     <h1>this is h1 two</h1>
17     <h1>this is h1 stree</h1>
18     <a href="http://baidu.com">this is a href.</a>
19 </body>
20 </html>
21 """
22 bs = BeautifulSoup(html, "lxml")
23 print bs.find_all('h1')