Save all regex matches on a vector

Question

So, I need to create a function that gets all occurrence matches on one string based on a regex, then store them in an array to ultimately choose an arbitrary capture group number within an individual match. I tried this:

std::string match(std::string basestring, std::string regex, int index, int group) {
    std::vector<std::smatch> match;
    (here I would need to create a while statement that iterates over all matches, but I'm not sure what overload of 'regex_search' I have to use)
    return match.at(index)[group]; }

I thought of getting a match and then starting to search just next to the end position of that match, in order to get the next one, when no match was found we assume that there are no more matches, and so the while statement is over, then the index and group arguments would get the desired capture group within a match. But I can't seem to find a 'regex_search' overload that requires a starting (or starting and end) positions as well as requiring the target string.

I can't answer your question without a bit more detail, but I've added a link to a good example of `regex_token_iterator` which I believe is what you are looking for: https://stackoverflow.com/a/47833633/2642059 — Jonathan Mee, Jun 23 '18 at 03:53

score -1 · Accepted Answer · answered Jun 23 '18 at 05:27

I found the solution myself after some hours of digging, this code will do the job:

std::string match(std::string s, std::string r, int index = 0, int group = 0) {
    std::vector<std::smatch> match;
    std::regex rx(r);
    auto matches_begin = std::sregex_iterator(s.begin(), s.end(), rx);
    auto matches_end = std::sregex_iterator();
    for (std::sregex_iterator i = matches_begin; i != matches_end; ++i) { match.push_back(*i); }
    return match.at(index)[group]; }

Save all regex matches on a vector

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