Well, it can be done without a temporary variable, but I'm not sure you would want to. Anyway...
## simplified example > a <- 1 > vname <- "a" > eval(substitute(attr(x,"b") <- "hi", list( x = as.name(vname)))) > a [1] 1 attr(,"b") [1] "hi" Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Wed, Oct 10, 2018 at 9:48 PM Peter Langfelder <peter.langfel...@gmail.com> wrote: > oops, I think the right code would be > > x = get(varname) > attr(x, "foo") = "bar" > assign(varname, x) > > On Wed, Oct 10, 2018 at 9:30 PM Peter Langfelder < > peter.langfel...@gmail.com> > wrote: > > > I would try something like > > > > x = get(myvarname) > > attr(x, "foo") = "bar" > > assign(varname, x) > > > > HTH, > > > > Peter > > > > On Wed, Oct 10, 2018 at 9:15 PM Marc Girondot via R-help < > > r-help@r-project.org> wrote: > > > >> Hello everybody, > >> > >> Has someone the solution to set attribute when variable is known by > name ? > >> > >> Thanks a lot > >> > >> Marc > >> > >> Let see this exemple: > >> > >> # The variable name is stored as characters. > >> > >> varname <- "myvarname" > >> assign(x = varname, data.frame(A=1:5, B=2:6)) > >> attributes(myvarname) > >> > >> $names > >> [1] "A" "B" > >> $class > >> [1] "data.frame" > >> $row.names > >> [1] 1 2 3 4 5 > >> > >> # perfect > >> > >> attributes(get(varname)) > >> > >> # It works also > >> > >> $names > >> [1] "A" "B" > >> $class > >> [1] "data.frame" > >> > >> $row.names > >> [1] 1 2 3 4 5 > >> > >> attributes(myvarname)$NewAtt <- "MyAtt" > >> > >> # It works > >> > >> attributes(get(varname))$NewAtt2 <- "MyAtt2" > >> Error in attributes(get(varname))$NewAtt2 <- "MyAtt2" : > >> impossible de trouver la fonction "get<-" > >> > >> # Error... > >> > >> ______________________________________________ > >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > >> 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 -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.