Confusing with Regex? How to read Regex

Asked Dec 05 '18 at 20:34

Active Dec 05 '18 at 20:41

Viewed 28 times

Consider that I'm working on Java programming language

Note that this regex is trying to determine whether the input is Ipv6 format or not.

There is a regex:

String regex = "^([a-fA-F0-9]{0,4}[:]){4,7}([a-fA-F0-9]{0,4})$";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(input);
    if (matcher.find())
        System.out.println(input);

I am confused with ^ this character.

Is it covers ([a-fA-F0-9]{0,4}[:]) this one?
Or all statements ^([a-fA-F0-9]{0,4}[:]){4,7}([a-fA-F0-9]{0,4})$?
And what is the purpose of this character?
Is this regex restricting each String (seperated by (semicolon): ) can length max 4 or not?

Basically, how to read this regex?

edited Dec 05 '18 at 20:41

asked Dec 05 '18 at 20:34

monstereo

@jonrsharpe this regex is trying to determine whether the input is Ipv6 format or not. – monstereo Dec 05 '18 at 20:41
It doesn't matter, the duplicate goes through regex syntax in general. A Q&A for every possible regex wouldn't scale very well! – jonrsharpe Dec 05 '18 at 20:43
See explanation: https://regex101.com/r/FYnZqS/1 – Jared Rummler Dec 05 '18 at 20:45

Confusing with Regex? How to read Regex

0 Answers0