Hi, Change: aa$z<- eval(parse(text=bb))
aa # x y z #1 2 3 3 #2 4 5 7 #3 6 7 11 A.K. I want to create a new column to a data frame using a formula from another variable: Example: I have a data set "aa" is; x y 2 3 4 5 6 7 My R code is; >bb <- "x+y-2" >attach(aa) >aa$z<- bb >detach(aa) the result is; x y z 2 3 x+y-2 4 5 x+y-2 6 7 x+y-2 but I want like; x y z 2 3 3 4 5 7 6 7 11 Could you please help me.. ______________________________________________ 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.