Regex - is it possible to find overlaping groups?

Question

I\'m new to regex and just want to know if its possible to find \"overlaping\" groups in the matches.

assume the following string:

20122 0029431

Answer 1

Yes, if you use lookahead assertions in combination with capturing groups:

Regex regexObj = new Regex(@"(?=(\d{4}\s\d{4}\s\d{4}))");
Match matchResult = regexObj.Match(subjectString);
while (matchResult.Success) {
    resultList.Add(matchResult.Groups[1].Value);
    matchResult = matchResult.NextMatch();
}