How to match version substring within overall string

I am trying to match a version substring with regex in the form of v###.##.### or version #.##.###. The number of version numbers doesn’t matter and there may or may not be a space after the v or version. This is what I was trying so far but it’s not matching in some cases:

\bv\s?[\d.]*\b|\bversion\s?[\d.]*\b

For example, it matches "version 6.2.11" but not c2000_v6.2.11. I’m relatively new to regex and not sure what I’m doing wrong here. I’m pretty sure there’s a better way to do the "or" part as well, so any help would be appreciated thank you!

>Solution :

First, your pattern can be shortened considerably by implementing an optional non-capturing group so that v or version could be matched without the need of an alternation.

Next, the first \b requires a word boundary but the version information starts after _ in the second expected match, and _ is a word char.

You can use

(?<![^\W_])v(?:ersion)?\s?[\d.]*\b

See the regex demo.

Details:

• (?<![^\W_]) – immediately on the left, there can be no letter or digit
• v – a v char
• (?:ersion)? – an optional ersion string
• \s? – an optional whitespace
• [\d.]* – zero or more digits or dots
• \b – a word boundary.