One reason might be that you can easily fool the user into running unexpected/unreadable commands. Guess what this does:
cmd <- paste(c(letters[c(19L, 25L, 19L, 20L, 5L, 13L)], "(' ", letters[c(19L, 21L, 4L, 15L)], " ", letters[c(4L, 5L, 19L, 20L, 18L, 15L, 25L)], " ", letters[c(1L, 12L, 12L)], " ')"), collapse="") ## not run ## eval(parse(text=cmd)) b. On 19 January 2012 11:05, Wet Bell Diver <wetbelldi...@gmail.com> wrote: > > for my info, why is this rarely a good idea? Is that the case for this > particular example , or is eval(paste()) generally rarely a good idea? > > --Peter > > Op 18-1-2012 22:22, R. Michael Weylandt schreef: > >> eval(parse(text = a)) >> >> But this is rarely a good idea....perhaps you could say a little more >> about your overall goal and we could direct you to a more "R"-ish >> solution? >> >> library(fortunes) >> fortune("rethink") >> >> Michael >> >> On Wed, Jan 18, 2012 at 4:18 PM, Ajay Askoolum<aa2e...@yahoo.co.uk> >> wrote: >>> >>> Given >>> >>> a<-"c(1,2,3,4,5)" >>> >>> How can I evaluate the variable a to return a (numeric) vector >>> comprising of 1,2,3,4,5? Thanks. >>> >>> [[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. >>> >> ______________________________________________ >> 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. > > > ______________________________________________ > 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. ______________________________________________ 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.