Try this:

replace(gsub(".*\\((.*)\\)$", "\\1", tests), !grepl("\\(.*\\)", tests), "")


On Wed, Oct 13, 2010 at 3:16 PM, Bart Joosen <bartjoosen@hotmail.com> wrote:

>
> Hi,
>
> this should be an easy one, but I can't figure it out.
> I have a vector of tests, with their units between brackets (if they have
> units).
> eg tests <- c("pH", "Assay (%)", "Impurity A(%)", "content (mg/ml)")
>
> Now I would like to hava a function where I use a test as input, and which
> returns the units
> like:
> f <- function (x) sub("\\)", "", sub("\\(", "",sub("[[:alnum:]]+","",x)))
> this should give "", "%", "%", "mg/ml", but it doesn't do the job quit
> well.
>
> After searching in the manual, and on the help lists, I cant find the
> answer.
>
> anyone?
>
> Bart
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Regular-expression-to-find-value-between-brackets-tp2994166p2994166.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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