How to find an IP pattern in a string

Question

I am trying to find an IP pattern or any similar pattern in a string. for example:

Text_1 = "Hello this ip is valid: 123.22.33.22 , but!" #expect 123.22.33.22

Text_2 = "this could be the second valid ip: 323.123.22.33.22 , but!" #expect 323.123.22.33.22

Text_3 = "third pattern is: 01.002.33.222 , but!" #expect 01.002.33.222

Text_4 = "fourth pattern is: 332.332.222 , but!" #expect 332.332.222

In all cases I need to extract all numbers which are separate by dots and later on evaluate if they are potentially valid or not.

I had a look to this question and this question, but all have some issues!

This is what I found but does not work perfectly as it can't catch the string longer than 4-digit:

import re
re.search(r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}', s).group()

This is confusing as most of these are not valid IP addresses. — Peter Wood, Dec 21 '19 at 09:10
If you're just looking for dotted digit sequences, how about `\d+(\.\d+)*`? — L3viathan, Dec 21 '19 at 09:11
Yes I am trying to extract these numbers to evaluate later if they are valid IP or not. Because none of solutions in aforementioned links do not give a valid solution to validate the IP, that's why I am trying to first extract numbers — Braiano, Dec 21 '19 at 09:13
@ I think this is not correct as I don't know the number of digits separated by dots in the input string — Braiano, Dec 21 '19 at 09:20

score 0 · Answer 1 · answered Dec 21 '19 at 09:19

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How about: map(int, “167.78.2.99”.split(“.”))) (split by . And try to convert each to an integer) and check for type error, check if len() is 4 and check for each element 0<=el<256.

Sorry for no code, not at my computer

answered Dec 21 '19 at 09:19

Lars

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Thanks for your answer, but how did you extract that 4-digits/5-digits/3-digits numbers from my provided strings? – Braiano Dec 21 '19 at 09:26
Oops, did not read the question well enough, i guess you could use answer 1, or if you do not like re, split on spaces, go over each word and strip it of anything but numbers and use the code i gave. – Lars Dec 23 '19 at 08:24

Jaideep Shekhar · Accepted Answer · 2019-12-21T09:43:18.027

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If you want any sequence of numbers and dots, try this:

# Find a number, then one or more ".numbers"
re.search(r'(\d+)(\.(\d+))+', Text_2).group()

It gives:

'323.123.22.33.22'

Note: After extracting candidates, you can check it with the regex provided by this answer.

edited Dec 21 '19 at 09:43

answered Dec 21 '19 at 09:21

Jaideep Shekhar

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@Readers, should I explain the regex more? Or some more examples? As it is, the answer may not be too useful... – Jaideep Shekhar Dec 21 '19 at 09:37

oppressionslayer · Answer 3 · 2019-12-21T09:55:22.863

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This finds exact ip addresses:

^(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)(?:\.(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)){3}$

https://regex101.com/r/3biYkC/1

Update, i added a word boundry to it, it seems to work:

\b(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)(?:\.(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)){3}\b

https://regex101.com/r/3biYkC/2

edited Dec 21 '19 at 09:55

answered Dec 21 '19 at 09:37

oppressionslayer

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But how would it extract the IP address from the original string? This can be definitely applied _after_ extracting possible matches. – Jaideep Shekhar Dec 21 '19 at 09:40
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@JaideepShekhar True, I'll put some thought around it and make a new version that may find it anywhere. – oppressionslayer Dec 21 '19 at 09:48
@JaideepShekhar check the second one out, it seems to work well. You can test more cases at the regex101 site – oppressionslayer Dec 21 '19 at 09:55
Lol. `-25.1.3.2` is being matched by ignoring the `-`. Should we check the minus in the regex as well? – Jaideep Shekhar Dec 21 '19 at 10:01
lol, you could add a space after the \b to not match concatenated IP's touching other things. idk, i'm sure some more work could be put to it. – oppressionslayer Dec 21 '19 at 10:07

How to find an IP pattern in a string

3 Answers3