MLR: Function "predict.WrappedModel" not found

Question

I am using R 3.6.1, RStudio 1.2.5019 and mlr 2.15.0. Mlr ist installed and loaded. Only mlr and the packages mlr is built on are loaded.

Now, I have trained a model using train and would like to test it on new data. Therefore, I want to use the predict.WrappedModel function from mlr.

If I call ?predict.WrappedModel I get all the information in the help window.

However, if I want to run predict.WrappedModel R throws an error indicating that the function cannot be found:

my_test = predict.WrappedModel(object = my_model, task = my_task)

konnte Funktion "predict.WrappedModel" nicht finden

Even when specifying mlr as the package to look in for the function:

my_test = mlr::predict.WrappedModel(object = my_model, task = my_task)

Fehler: 'predict.WrappedModel' ist kein von 'namespace:mlr' exportiertes Objekt

I also tried using ?predict , but here I also got an error:

my_test = mlr::predict(object = my_model, task = my_task)

Fehler: 'predict' ist kein von 'namespace:mlr' exportiertes Objekt

I've already spent a lot of time trying to fix this issue and read all the related questions I had found here and on the mlr forum on github, but could not find a solution.

What am I missing here?

Thanks a lot in advance :)

Answer 1

You neither need predict.WrappedModel nor mlr::predict. Both are internal functions using the generic S3 approach in R to operate based on the class of the supplied R object.

So in this case, as long as you pass a object derived from a mlr::train() call everything will just work.

Speaking with code:

library("mlr")
my_model = train(learner, task)
predict(my_model, task)