正则表达式注意事项

1.所谓组。您检查一次，你可以选择多个比赛结果，每个结果是指一组

eg.

import re
pattern = re.compile(r'<div(.*?
>)(.*?)</div>')
match = pattern.match('<div class="test">Hello <div>wa haha<div>test xxx</div></div>world</div>')
if match:
  print match.group(2)
  print match.group(1)
  print match.group(0)


>>> ================================ RESTART ================================
>>> 
Hello <div>wa haha<div>test xxx
 class="test">
<div class="test">Hello <div>wa haha<div>test xxx</div>
>>>

当中group(0)比較特殊，全部组的合集

2.查找一个文件里全部的http（url）地址

import re
import urllib2
f = open('url.txt','r')
string = ""
while 1:
    line = f.readline()
    if not line:break
    string += line

f.close()

urls = re.findall('http[s]?://(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*(),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+', string)

3.正则表达式空格含有 fv如几个字符