On Mon, Jan 10, 2011 at 8:23 PM, analys...@hotmail.com <analys...@hotmail.com> wrote: > an example available on the net goes like > >> df > identifier quantity > 1 1 10 > 2 1 20 > 3 2 30 > 4 1 15 > 5 2 10 > 6 3 20 >> aggregate(df$quantity, by=list(df$identifier), sum) > Group.1 x > 1 1 45 > 2 2 40 > 3 3 20 > > > I'd like Group.1 to retain the name "identifier" and would like to > control what "x" get called in the output. Thanks.
Try these: > aggregate(quantity ~ identifier, df, sum) identifier quantity 1 1 45 2 2 40 3 3 20 > > aggregate(df["quantity"], df["identifier"], sum) identifier quantity 1 1 45 2 2 40 3 3 20 > > aggregate(list(Quantity = df$quantity), df["identifier"], sum) identifier Quantity 1 1 45 2 2 40 3 3 20 -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com ______________________________________________ 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.
