If you have a data frame "df" with a column "JT" Try this one: str <- "df$JT == 12"
fun<-function(str){b<-eval(parse(text=str)) return(b)} fun(str) On Mon, Sep 17, 2012 at 11:57 AM, Christof Kluß <ckl...@email.uni-kiel.de>wrote: > Hi > > I would like to have something like > > str <- "df$JT == 12" > > fun <- function(df) { > > b <- eval(parse(str)) > > return(b) > } > > but for performance "eval(parse(a))" should not be evaluated at each > function call, but should work as > > fun <- function(df) { > > b <- df$JT == 12 > > return(b) > } > > Do you have an idea how I can implement this? > > Thx > Christof > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]]
______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.