getting names subgroups

Question

I am working with the new version of boost 1.42 and I want to use regex with named sub groups. Below an example.

std::string line("match this here FIELD=VALUE in the middle");
boost::regex rgx("FIELD=(?<VAL>\\w+)", boost::regex::perl );
boost::smatch thisMatch;
boost::regex_search( line, thisMatch, rgx );

Do you know how to get the content of the match ? The traditional way is

std::string result( mtch[1].first, mtch[1].second );

but i don't want to use this way.

I want to use the name of the subgroups as usual in Perl and in regex in general. I tried this, but it didn't work.

std::string result( mtch["VAL"].first, mtch["VAL"].second );

Do you know how to get the value using the name of the subgroup?

Thanks AFG

What's the difference between the way you want and the way you don't want? The statements are exactly the same. — kennytm, Mar 12 '10 at 12:59
Hi again! Have a look below 'cos I found what I needed! Have a nice week end! — Abruzzo Forte e Gentile, Mar 12 '10 at 16:21
+1 'cause this just helped me correct a stupid error from Python regexes in C++: Named groups in Python are with `(?P...)` — Felix Dombek, Jan 05 '11 at 13:34

score 1 · Accepted Answer · answered Mar 12 '10 at 12:56

1

AFAIK, there is no such option. See Understanding Marked Sub-Expressions and Captures and in particular the table on Perl and Boost.Regex equivalence. You will need to use the boost::match_results<IteratorType> to access any and all matches.

answered Mar 12 '10 at 12:56

dirkgently

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Hi dirkgently! I thank you for the URL. I found the solution, please see what I wrote below! Have a nice week end! – Abruzzo Forte e Gentile Mar 12 '10 at 16:20

score 1 · Answer 2 · edited Jan 29 '16 at 16:18

1

I finally found what I want to achieve.

std::cout << mtch["VAL"] << std::endl;

I tried and it will work without any problems.

I think that is a feature available only since version 1.42 of boost, but I am not sure.

edited Jan 29 '16 at 16:18

Vincent Savard

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answered Mar 12 '10 at 16:11

Abruzzo Forte e Gentile

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getting names subgroups

2 Answers2