Dear list, # I have a DF like this: sleep$b <- c(rep(8,10), rep(9,10)) sleep$me <- with(sleep, ave(extra, group, FUN = mean)) sleep # I would like to create a new variable # holding the b-th value of group 1 and 2. # This is not what I want, it takes always the '8' from group '1' # and not the '9' sleep$gr <- with(sleep, ave(extra, group, FUN = function(x) x[ b[1] ])) sleep Thanks for any help! Patrick
Patrick Hausmann <Patrick.Hausmann <at> uni-bremen.de> writes:> # I have a DF like this: > sleep$b <- c(rep(8,10), rep(9,10)) > sleep$me <- with(sleep, ave(extra, group, FUN = mean)) > sleep > > # I would like to create a new variable > # holding the b-th value of group 1 and 2. > > # This is not what I want, it takes always the '8' from group '1' > # and not the '9' > sleep$gr <- with(sleep, ave(extra, group, FUN = function(x) x[ b[1] ])) > sleepNice example, but I don't fully understand what you want. sleep$b[1] 8 Or could it be that you got into the factor-trap? Try R-FAQ How-do-I-convert-factors-to-numeric_003f Dieter
Try performing ave over the indexes rather than over extra itself: sleep$newcol <- with(sleep, ave(1:nrow(sleep), group, FUN = function(ix) extra[b[ix][1]])) On Mon, Mar 2, 2009 at 4:28 AM, Patrick Hausmann <Patrick.Hausmann at uni-bremen.de> wrote:> Dear list, > > # I have a DF like this: > sleep$b ? <- c(rep(8,10), rep(9,10)) > sleep$me ?<- with(sleep, ave(extra, group, FUN = mean)) > sleep > > # I would like to create a new variable > # holding the b-th value of group 1 and 2. > > # This is not what I want, it takes always the '8' from group '1' > # and not the '9' > sleep$gr ?<- with(sleep, ave(extra, group, FUN = function(x) x[ b[1] ])) > sleep > > Thanks for any help! > Patrick > > ______________________________________________ > R-help at 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. >