python 正则

1.正则有三种匹配方法

import re

re.match #从开始位置开始匹配，如果开头没有则无

re.search #搜索整个字符串

re.findall #搜索整个字符串，返回一个list

2.'|'  或规则

import re

s = 'I have a dog , I have a cat ,I have a dog'

r = re.findall(r'I have a (dog|cat)',s)

for i in r:print i

'''

dog

cat

dog

[Finished in 0.2s]

'''

r = re.findall(r'I have a (?:dog|cat)',s)

for i in r:print i

'''

I have a dog

I have a cat

I have a dog

[Finished in 0.2s]

'''

 --------实例------------

import re

data = '''