Adabag package in R

Question

I am trying to perform classification using R's adabag package.

The following call works perfectly with R's ada package's ada() function.

model<-ada(factor(label)~., data=trainingdata)

But when the same training data set is used in the following adabag's function call, it returns an error:

model<-boosting(factor(label)~., data=trainingdata)

Error in `[.data.frame`(data, , as.character(formula[[2]])) : 
undefined columns selected

What this error suggests exactly?

Answer 1

I get exactly that error message when running a minor modification of boosting's first example:

> data(iris)
> iris.adaboost <- boosting(factor(Species)~., data=iris, boos=TRUE, mfinal=10)
Error in `[.data.frame`(data, , as.character(formula[[2]])) : 
  undefined columns selected

So you should try the advice I just gave in a comment (to do the factor()-ing beforehand). The formula interface to boosting is not full featured enough to even handle the factor function in its parse-tree.