小菜的正则（备忘而已）

为接下来的学习做铺垫

从文本中匹配ip，并返回ip的一个列表

>>> line = "192.31.31.1 wfffwqfwqfqfqfqfq"
>>> ip = re.findall('(?<![.d])(?:d{1,3}.){3}d{1,3}(?![.d])',line)
>>> ip
['192.31.31.1']
>>> ip[0]
'192.31.31.1'

匹配某个字符串是否满足结构

>>> ip
['219.143.68.112', '219.143.68.112', '219.143.68.112', '219.143.68.112', '219.14
3.68.112']
>>> if re.match('^(10|127|172|192)+.d+.d+.d+',ip[0]):
...     print "True"
...
>>> if re.match('^(10|127|172|192|219)+.d+.d+.d+',ip[0]):
...     print "ok"
...
ok
>>>

>>> line = "127.0.0.1"
>>> ip = re.findall(r'd+.d+.d+.',line)
>>> ip
['127.0.0.']
>>> ip[0]
'127.0.0.'