Hi, is it true that the only way to tell rpart which variables to use is to specify every single variable in the formula and separate them with "+"? I wonder if this error...> rotree <- rpart(powerdata[,1]~powerdata[,2:3],+ method="class") Error in model.frame(formula, rownames, variables, varnames, extras, extranames, : invalid variable type ...can be prevented by other means than...> rotree <- rpart(segments~V1.3+V1.9,+ method="class",data=powerdata) This works. (The variables here are powerdata[,1] and [,2:3].) But I do not want to write 200 variable names down, as this is the real size of "powerdata". Is there any way around that? Christian *********************************************************************** Christian Hennig Fachbereich Mathematik-SPST/ZMS, Universitaet Hamburg hennig at math.uni-hamburg.de, http://www.math.uni-hamburg.de/home/hennig/ ####################################################################### ich empfehle www.boag-online.de
Christian Hennig wrote:> Hi, > > is it true that the only way to tell rpart which variables to use > is to specify every single variable in the formula and separate them with > "+"? > > I wonder if this error... > > >>rotree <- rpart(powerdata[,1]~powerdata[,2:3], > + method="class") > Error in model.frame(formula, rownames, variables, varnames, extras, > extranames, : > invalid variable type > > ...can be prevented by other means than... > > >>rotree <- rpart(segments~V1.3+V1.9, > > + method="class",data=powerdata) > > This works. > (The variables here are powerdata[,1] and [,2:3].) > > But I do not want to write 200 variable names down, as this is the real > size of "powerdata". > > Is there any way around that? > > ChristianConsider to use rotree <- rpart(segments ~ ., method = "class", data = powerdata) The "." defines all variables in powerdata, except for "segments", as usual for formulas. Uwe Ligges> > > *********************************************************************** > Christian Hennig > Fachbereich Mathematik-SPST/ZMS, Universitaet Hamburg > hennig at math.uni-hamburg.de, http://www.math.uni-hamburg.de/home/hennig/ > ####################################################################### > ich empfehle www.boag-online.de > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
On 16 Apr 2004 at 17:08, Christian Hennig wrote: You can build your formula along the ways of the following example, without typing the 200 names:> nam <- paste("var", 1:5, sep="", collapse="+") > nam[1] "var1+var2+var3+var4+var5"> nam <- paste("y", nam, sep="~") > nam[1] "y~var1+var2+var3+var4+var5"> as.formula(nam)y ~ var1 + var2 + var3 + var4 + var5 Kjetil Halvorsen> Hi, > > is it true that the only way to tell rpart which variables to use is > to specify every single variable in the formula and separate them with > "+"? > > I wonder if this error... > > > rotree <- rpart(powerdata[,1]~powerdata[,2:3], > + method="class") > Error in model.frame(formula, rownames, variables, varnames, extras, > extranames, : > invalid variable type > > ...can be prevented by other means than... > > > rotree <- rpart(segments~V1.3+V1.9, > + method="class",data=powerdata) > > This works. > (The variables here are powerdata[,1] and [,2:3].) > > But I do not want to write 200 variable names down, as this is the > real size of "powerdata". > > Is there any way around that? > > Christian > > > > ********************************************************************** > * Christian Hennig Fachbereich Mathematik-SPST/ZMS, Universitaet > Hamburg hennig at math.uni-hamburg.de, > http://www.math.uni-hamburg.de/home/hennig/ > ###################################################################### > # ich empfehle www.boag-online.de > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html