正则表达式包括和排除某些IP [英] Regex to include and exclude certain IPs

问题描述

我有一个功能齐全的python 2.7代码，可从路由表中提取IP.它仅提取x.x.x.x/xx格式的ip.但是，我确实有一个问题，排除了路由表中的某些行.

例如，这一行:

D       10.50.80.0/24 [90/3072] via 10.10.10.1, 3w6d, Vlan10

在这一行中，我只关心10.50.80.0/24.由于这是唯一带有/24表示法的ip，因此我只能抓住它并让regex一次忽略/(例如10.10.10.1).但是在表中，我们有以下2个异常:

     10.10.60.0/16 is variably subnetted, 58 subnets, 4 masks
C       10.10.140.0/24 is directly connected, Vlan240

我想在第二行(10.10.140.0/24)而不是第一行(10.10.60.0/16)上捕获IP.该程序正在提取IP，并检查表中是否有可用的子网.出现了10.10.60.0/16，因为它不是在表10.10.60.0/16，而是在说此子网具有可变子网划分.

当前，我的工具正在捕获该IP，并在表中标记了整个10.10.60.0/16范围，这是不正确的.我尝试了一些正则表达式编辑，但对此并不满意.我不想意外地跳过任何子网，尤其是与第一行类似的第二行.捕获所有正确的子网非常重要.

有人可以建议最好的正则表达式编辑来完成此操作.仅将具有 x.x.x.x/xx的跳过行划分为子网，x个子网，x个掩码

这是我当前的代码:

match = re.findall(r'(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\/(?:[\d]{1,3})', text)

谢谢 达蒙

解决方案

如果我正确地回答了您的问题，则希望您现有的正则表达式跳过任何IP地址/子网，后跟可变子网划分" .为此，您可以使用此正则表达式:

(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\/(?:[\d]{1,3})\b(?! is variably)

• 我在您的正则表达式末尾添加了\b(?! is variably)
末尾的
• \b表示单词边界
• (?! is variably)的前瞻性(?!为负，可确保IP/子网后不存在文本可变".

演示: https://regex101.com/r/jTu8cj/1

比赛:

D       10.50.80.0/24 [90/3072] via 10.10.10.1, 3w6d, Vlan10
C       10.10.140.0/24 is directly connected, Vlan240

不匹配:

10.10.60.0/16 is variably subnetted, 58 subnets, 4 masks
255.255.255.1

I have a functional python 2.7 code that extracts IPs from the routing table. It only extracts ip in x.x.x.x/xx format. I do however has a issue excluding some lines in the route table.

For example, this line:

D       10.50.80.0/24 [90/3072] via 10.10.10.1, 3w6d, Vlan10

In this line all I care about is 10.50.80.0/24. Since this is the only ip with /24 notation, I can only grab that and have regex ignore onces without / (e.g, 10.10.10.1). But in the table, we have below 2 anomalies:

     10.10.60.0/16 is variably subnetted, 58 subnets, 4 masks
C       10.10.140.0/24 is directly connected, Vlan240

I would like to capture the IP on second line (10.10.140.0/24) but not first line (10.10.60.0/16). The program is extracting IPs and checking if any subnet is available in table or not. 10.10.60.0/16 is issue as it is not saying that 10.10.60.0/16 is in table but only saying that this subnet has variable subnetting.

Currently my tool is capturing this IP and marking whole 10.10.60.0/16 range as in table which is not true. I tried some regex edit but was not really happy with it. I do not accidentally want to skip any subnet accidentally especially the second line that is similar to first. It is very important to capture all correct subnets.

Can someone suggest a best regex edit to accomplish this. Only skip lines that has x.x.x.x/xx is variably subnetted, x subnets, x masks

Here is my current code:

match = re.findall(r'(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\/(?:[\d]{1,3})', text)

Thanks Damon

解决方案

If I got your question correctly you want your existing regex to skip any IP/subnet that is followed by 'is variably subnetted'. Do that that you can use this regex:

(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\.(?:[\d]{1,3})\/(?:[\d]{1,3})\b(?! is variably)

• I've added \b(?! is variably) at the end of your regex
• \b at the end indicates a word boundary
• (?! is variably) has a negative lookahead (?! which makes sure that the text ' is variably' isn't present after the IP/subnet.

Demo: https://regex101.com/r/jTu8cj/1

Matches:

D       10.50.80.0/24 [90/3072] via 10.10.10.1, 3w6d, Vlan10
C       10.10.140.0/24 is directly connected, Vlan240

Doesn't match:

10.10.60.0/16 is variably subnetted, 58 subnets, 4 masks
255.255.255.1

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