Hi Judith, You should use double brackets, like this:
df[[variab]]<-factor(df[[variab]], levels=c("A2B","B31","C33")) see ?"[" for details, noting that the help page assumes that you know data.frames are list-like objects. Best, Ista On Mon, Feb 6, 2012 at 2:03 PM, Judith Flores <jur...@yahoo.com> wrote: > Hello R-users, > > I have a data frame whose names of columns I don't know a priori, but the > user of my code will know them. The user is supposed to save the name of the > column that will need some reordering of the levels of the factor later on. > The name of the column will be saved in an object called: > > variab > > the data frame is called df. > > > If I try to the do following: > > df[variab]<-factor(df[variab], levels=c("A2B","B31","C33")) > > it won't work because df[variab] is a data frame. The reason for reordering > the levels of the factor is because once that variable is plotted, the levels > of the factor need to appear in certain order. > > How can I re-order the levels of a factor whose name I don't know? > > > Thank you, > > Judith > [[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.