在R中使用gregexpr按名称访问正则表达式组结果

Question

How can I access all matches with groupings (ie label ) using gregexpr() in R?

s <- "aaa123bbb345ccc"
p <- "(?<label>\\d+)"
m <- gregexpr(p, s, perl = TRUE)

I am interested in printing the matches in m but referencing the group name <label1> . This can be easily done in C# but I'm struggling in R and I cannot figure out how to do this from the CRAN docs.

Edit: C# code below requested by G Grothendieck :

string s = "aaa123bbb345ccc";
string p = @"(?<label>\d+)";
Regex r = new Regex(p);
Match m = r.Match(s);
if (m.Success)
{
    Console.WriteLine(m.Groups["label"].Value);
}

Answer 1

This will return only the substrings associated with label .

st <- attr(m[[1]], "capture.start")[, "label"]
len <- attr(m[[1]], "capture.length")[, "label"]
substring(s, st, st + len - 1)
## [1] "123" "345"