In R, is it possible to extract group capture from a regular expression match? As far as I can tell, none of grep
, grepl
, regexpr
, gregexpr
, sub
, or gsub
return the group captures.
I need to extract key-value pairs from strings that are encoded thus:
\((.*?) :: (0\.[0-9]+)\)
I can always just do multiple full-match greps, or do some outside (non-R) processing, but I was hoping I can do it all within R. Is there's a function or a package that provides such a function to do this?
str_match()
, from the stringr
package, will do this. It returns a character matrix with one column for each group in the match (and one for the whole match):
> s = c("(sometext :: 0.1231313213)", "(moretext :: 0.111222)")
> str_match(s, "\\((.*?) :: (0\\.[0-9]+)\\)")
[,1] [,2] [,3]
[1,] "(sometext :: 0.1231313213)" "sometext" "0.1231313213"
[2,] "(moretext :: 0.111222)" "moretext" "0.111222"