Can I use an OR in regex without capturing what's enclosed?

Question

I have used RegExp before but am far from an expert...

I'm reading up right now for a project, but am running into an issue. I'm using rubular.com to build my regex, and their documentation describes the following:

(...)   Capture everything enclosed
(a|b)   a or b

How can I use an OR expression without capturing what's in it? So if I want to match "a or b followed by a c", and only capture the c, I can't use

(a|b)(c)

right? Then I capture both the "a or b" as well as the "c". I know I can filter through the captured results, but that seems like more work...

Am I missing something obvious? I'm using this in Java, if that is pertinent.

Thank you for your help!

Answer 1

Depending on the regular expression implementation you can use so called non-capturing groups with the syntax (?:…):

((?:a|b)c)

Here (?:a|b) is a group but you cannot reference its match. So you can only reference the match of ((?:a|b)c) that is either ac or bc.

Answer 2

If your implementation has it, then you can use non-capturing parentheses:

(?:a|b)

Answer 3

Even rubular doesn't make you use parentheses and the precedence of | is low. For example a|bc does not match ccc