请教一个正则匹配多行问题的

[TOUJOURSER]

文本内容:

 network-object host 109.17.49.131
object-group network KaGuan_12
 network-object host 109.17.26.11
 network-object host 109.17.26.12
object-group network ShangHai
 network-object host 110.1.60.91
 network-object host 110.1.60.92
 network-object host 110.1.172.31
 network-object host 110.1.172.32
 network-object host 110.238.250.57
 network-object host 110.238.250.58
object-group network wangguan_test
 network-object host 111.17.13.32
object-group network wangguan_app_2
 network-object host 111.17.9.54
 network-object host 111.17.9.63

我现在想通过 110.1.172.32 这个字符串 匹配到 object-group network 后面的 ShangHai 这个关键词, 请问正则怎么写? 感谢各位大佬

[lululau]

正则正则，起码把规则说出来啊，你只举一个特例，那你直接把这个特例写成字符串字面量就可以了，不需要正则啊，再说，你这个说的 110.1.172.32 后面也没有 shanghai 啊

[TOUJOURSER]

@lululau 不好意思描述的不太清楚, 规则是根据 ip 去获取该 ip 所属于的 group.
我想通过 110.1.172.32 去向上查找以"object-group network "开头的那一行最后的 ShangHai 字符.

[araraloren]

自己字符串直接查找不行么，如果是在练习正则的话当我没说。。

[ClericPy]

import re

string = r'''network-object host 109.17.49.131
object-group network KaGuan_12
network-object host 109.17.26.11
network-object host 109.17.26.12
object-group network ShangHai
network-object host 110.1.60.91
network-object host 110.1.60.92
network-object host 110.1.172.31
network-object host 110.1.172.32
network-object host 110.238.250.57
network-object host 110.238.250.58
object-group network wangguan_test
network-object host 111.17.13.32
object-group network wangguan_app_2
network-object host 111.17.9.54
network-object host 111.17.9.63'''
ip = '110.1.172.32'.replace('.', r'\.')
result = re.search(
rf'object-group network (.*?)\n[\s\S]*?network-object host {ip}',
string)
if result:
print(result.group(1))
else:
print('Not found.')


KaGuan_12

[TOUJOURSER]

@ClericPy 感谢, 你写的这个只可以匹配出 KaGuan_12 , 但是我需要的是 ShangHai, 110.1.172.32 是属于 ShangHai group

[todd7zhang]

import re
a = ''' network-object host 109.17.49.131
object-group network KaGuan_12
network-object host 109.17.26.11
network-object host 109.17.26.12
object-group network ShangHai
network-object host 110.1.60.91
network-object host 110.1.60.92
network-object host 110.1.172.31
network-object host 110.1.172.32
network-object host 110.238.250.57
network-object host 110.238.250.58
object-group network wangguan_test
network-object host 111.17.13.32
object-group network wangguan_app_2
network-object host 111.17.9.54
network-object host 111.17.9.63
'''

re.findall(r'object-group network (\w+)(?:(?:(?!object-group).)*)(?=network-object host 110\.1\.172\.31)', a, re.DOTALL)

[ClericPy]

@TOUJOURSER #5 哦对了, 正则没法回溯取非贪婪的, 比较好的办法还是
1. 逐行分析解析成 ip: group 映射再查询
2. 或者是用 group 字段做 split 再查询

[ClericPy]

6 楼的零宽断言是个好方法, 先匹配非 group 再取 group

[TOUJOURSER]

@ClericPy @todd7zhang 真的非常感谢, 这个问题困扰了我好久

[qingshengwen]

试试这个看看
object\-group\snetwork\s(.*?)(?:\s*network\-object\shost\s\d+\.\d+\.\d+\.\d+\s*){0,}(?:\s*network\-object\shost\s110.1.172.32\s*)
https://imgur.com/a/loDyJo7

[no1xsyzy]

写个 FSM 不行吗？这还正则？（不超过十分钟写完）
https://gist.github.com/no1xsyzy/11ba23cd13f90b3f94227d4838fd7e5a

[corningsun]

用不上正则

如果只需要一次匹配，只是两次截取字符串的问题，代码示例如下：

https://gist.github.com/corningsun/87aac1ca2bc46e698a4d332a93118bbe

如果需要多次匹配，且数据量不大的话，最好的还是解析所有 IP，做哈希表查找比较好。