How get the priority in regex?

Question

I have a wrong regex

([A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9]*\.)

I need to accept strings like:

But i am not needing in this string - a-.

What should I change?

Can you explain in plain English what the regex rule is? – David Frank Jan 24 '16 at 14:00 — David Frank, Jan 24 '16 at 14:00
`[A-Za-z0-9](?:-[A-Za-z0-9\-])*[A-Za-z0-9]*\.` – Avinash Raj Jan 24 '16 at 14:01 — Avinash Raj, Jan 24 '16 at 14:01

ndnenkov · Answer 1 · 2016-01-24T14:08:12.653

1

[A-Za-z0-9]+\.|[A-Za-z0-9]+-?[A-Za-z0-9]\.

The idea is:

If you don't mind matching underscores too, you can use the word character set:

\w+\.|\w+-?\w\.

edited Jan 24 '16 at 14:08

answered Jan 24 '16 at 14:02

ndnenkov

I have understood the idea. Nice way!=) Thank U very much from Russia) – E.Simchuk Jan 24 '16 at 14:41

score 1 · Answer 2 · edited May 23 '17 at 11:59

1

You can try like this by using an optional group.

"(?i)[A-Z0-9](?:-?[A-Z0-9]+)*\\."

(?i) flag for caseless matching.
[A-Z0-9] one alphanumeric character
(?:-?[A-Z0-9]+)* any amount of (?: an optional hyphen followed by one or more alnum )
\. literal dot

edited May 23 '17 at 11:59

Community

answered Jan 24 '16 at 14:17

bobble bubble

Thank U a lot. What does mean '?:' ? – E.Simchuk Jan 24 '16 at 14:57
@E.Simchuk Welcome! `(?:` starts a [non capture group](http://stackoverflow.com/questions/3512471/what-is-a-non-capturing-group). – bobble bubble Jan 24 '16 at 15:01
@E.Simchuk, `(?:)` is basically the same as `()`, it just doesn't capture the group. It doesn't make a difference as far as matching goes. – ndnenkov Jan 24 '16 at 15:01

Bohemian · Answer 3 · 2016-01-24T15:15:42.037

1

This works for your test cases:

[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?\.

edited Jan 24 '16 at 15:15

answered Jan 24 '16 at 15:10

Bohemian

3 Answers3