Hi: To spare the OP from tearing his hair out over a nuance of regular expressions, here's a toy example:
df <- data.frame(key = paste('POSTOFF', 1:3, sep = '_'), as.data.frame(matrix(rpois(180, 10), ncol = 60))) nms <- scan(what = "") "key" "AMR.pa1.M" "AMR.pa2.M" "AMR.pa3.M" "AMR.pa4.M" "AMR.pa5.M" "AMR.pa6.M" "AMR.pa7.M" "AMR.pa8.M" "AMR.pa9.M" "AMR.pa10.M" "AMR.ta1.M" "AMR.ta2.M" "AMR.ta3.M" "AMR.ta4.M" "AMR.ta5.M" "AMR.ta6.M" "AMR.ta7.M" "AMR.ta8.M" "AMR.ta9.M" "AMR.ta10.M" "AMR.ka1.M" "AMR.ka2.M" "AMR.ka3.M" "AMR.ka4.M" "AMR.ka5.M" "AMR.ka6.M" "AMR.ka7.M" "AMR.ka8.M" "AMR.ka9.M" "AMR.ka10.M" "SMR.pa1.M" "SMR.pa2.M" "SMR.pa3.M" "SMR.pa4.M" "SMR.pa5.M" "SMR.pa6.M" "SMR.pa7.M" "SMR.pa8.M" "SMR.pa9.M" "SMR.pa10.M" "SMR.ta1.M" "SMR.ta2.M" "SMR.ta3.M" "SMR.ta4.M" "SMR.ta5.M" "SMR.ta6.M" "SMR.ta7.M" "SMR.ta8.M" "SMR.ta9.M" "SMR.ta10.M" "SMR.ka1.M" "SMR.ka2.M" "SMR.ka3.M" "SMR.ka4.M" "SMR.ka5.M" "SMR.ka6.M" "SMR.ka7.M" "SMR.ka8.M" "SMR.ka9.M" "SMR.ka10.M" names(df) <- nms dfm <- melt(df2, id = 'key') dfm2 <- cbind(dfm, colsplit(dfm$variable, split = '\\.', names = c('A', 'B', 'C'))) head(dfm2) That little \\ in front of the . in the split argument of colsplit matters. It took me about 10 minutes for the obvious to dawn on me...that the value fed to split has to obey regular expression rules :-} HTH, Dennis On Thu, Jan 20, 2011 at 1:01 PM, Hadley Wickham <had...@rice.edu> wrote: > >> I think I should be able to do this using the "reshape" function, but > >> I cannot get it to work. I think I need some help to understand > >> this... > >> > >> > >> (If I could split the "variable" into three separate columns splitting > >> by ".", that would be even better.) > > > > Use strsplit and "[" > > Or colsplit, from reshape, that does this for you. > > Hadley > > -- > Assistant Professor / Dobelman Family Junior Chair > Department of Statistics / Rice University > http://had.co.nz/ > > ______________________________________________ > 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.