Extract second last IP address from a list of IP using RegEx-CodePudding

I want to extract the second last IP address from the below expression using regex:

18.223.194.15, 56.99.45.32, 32.65.27.65, 52.89.22.5, 123.12.22.53

Should get 52.89.22.5 from the above

16.45.98.14, 10.22.102.16

Should get 16.45.98.14 from the above

I was able to get the last IP or the first IP using the below regex commands but I am having trouble getting the second last ip

To get the last IP

(?<IP>([0-9]{1,3}\.){3}[0-9]{1,3}) $

To get the first IP

(?<IP>([0-9]{1,3}\.){3}[0-9]{1,3}),.*

Thanks in advance

CodePudding user response：

You need a regex flavour with some form of lookahead/lookbehind.

This could take the form of a capture group surrounded by something.

Assume regex has basic form: ^A(xA)*$ or ^(Ax)*A$

A is something of interest. x is a separator.

In all cases, result is in second capture group.

CodePudding user response：

You can capture the second last one, and match the last one asserting the end of the string after it.

\b(?<IP>(?:[0-9]{1,3}\.){3}[0-9]{1,3}), (?:[0-9]{1,3}\.){3}[0-9]{1,3}$