Error message is self-explanatory: there is an unused parameter 'na.rm=TRUE'. You are calling your function 'truecost' which only has a single parameter 'time' and you are attempting to pass in 'na.rm=TRUE' which it will not accept. You don't need it.
On Fri, May 22, 2009 at 12:36 PM, Thomas Levine <thomas.lev...@gmail.com>wrote: > A subset of my raw data looks like this: > > -------------- > "Grip" "Technique" "Baseline.integrated" "Task" > "Stroke..direction." "Engag" "Disen" > "PenDG" "PenUG" "PenDS" > "PenUS" "Duration" > ------------- > "Tripod","Barrel","Integrated",7,"S70",230,510,270,510,781,1011,1011 > "Tripod","Barrel","Integrated",7,"S71","na","na","na","na","na","na","na" > "Round","NonPrefHand","Baseline",0,"S00","na","na",110,250,380,520,520 > "Round","NonPrefHand","Baseline",0,"S01","na","na",220,360,460,620,620 > -------------- > > > I computed some values (times) from the raw data > > > --------------- > t_p1=PenDG > t_c1=PenUG-PenDG > t_p2=PenDS-PenUG > t_c2=PenUS-PenDS > --------------- > > > And I put those times in a data frame called "times". For each of these > times, I want to subtract the average for "Baseline" trials from the > average > for "Integrated" trials within the "Grip" and "Technique" factors. Call > these differences the true cost of mode selection. > > > > truecost <- > > function(time){as.numeric(tapply(time,Baseline.integrated,mean,na.rm=T)[2]-tapply(time,Baseline.integrated,mean,na.rm=T)[1])} > > To help explain what the truecost function does: > > tapply(t_p1,Baseline.integrated,mean,na.rm=T) > Baseline Integrated > 212.8000 252.8402 > > truecost(t_p1) > [1] 40.04021 > > > Then I try to create a table of average truecost as a function of levels of > a factor. I think this is the same error with tapply and by. > > > > tapply(t_p1,list(Grip,Technique),truecost,na.rm=T) > Error in FUN(X[[1L]], ...) : unused argument(s) (na.rm = TRUE) > > by(times,list(Grip,Technique),truecost,na.rm=T) > Error in FUN(data[x, , drop = FALSE], ...) : > unused argument(s) (na.rm = TRUE) > > > Any ideas? > > > Thomas Levine! > > [[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<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? [[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.