R cannot find specific function in a package

Question

I'm using the randomForest package (v 4.6-7) in R (v 2.15.3) and can easily use the function randomForest to create a model. However, when I try to predict on my test set, the predict.randomForest function cannot be found. I've also tried plotting with plot.randomForest only to get the same error, "could not find function."

I've already tried reinstalling the package (figuring maybe it was out of date) and made sure the spelling is absolutely correct. I cannot figure out what's causing this error, any ideas?

Answer 1

It appears that the functions of interest are not exported from the package.

If you use ls(package:randomForest) you'll get a list of the exported functions.

If you want to see all the functions available the use: ls(getNamespace("randomForest"), all.names=TRUE) . Thanks @Joshua. You'll see the functions you want there.

In order to refer to one of them explicitly, use: randomForest:::predict.randomForest() or just make a object which inherits the class 'randomForest' and call predict() on it directly.