Need a rex to extract an ip address with a trailing port number

[mark_groenveld]

I would like to extract an ip address from a text field where the ip address has a trailing port number.

The text is like so:  X-Upstream:"11.111.11.11:81"

The extraction would provide only the ip address.

Thanks.

[ITWhisperer · Accepted solution]

| rex "(?<ip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})(?=:\d+)"

[PickleRick]

If I were to be nitpicky I'd say that it captures stuff like 000.999.123.987, which is not a valid IP 😉

[ITWhisperer]

True, but I didn't want to give away all my secrets! 😎😁

[PickleRick]

😁

But seriously, this solution is usually good enough unless you have a strict demand on validating the IP format in which case regex is not the best tool for the job (it can be done using regex but it's neither pretty, nor efficient).

[ITWhisperer]

We have used it in RegexGames although I can't remember how many came up with a solution. Yes, regex may not be "pretty", but can be fun trying to solve regex puzzles!