Extending

This chapter gives instructions on how to extend mlr3 and its extension packages with custom objects.

The approach is always the same:

determine the base class you want to inherit from,
extend the class with your custom functionality,
test your implementation
(optionally) add new object to the respective Dictionary.

The chapter Create a new learner illustrates the steps needed to create a custom learner in mlr3.

# Extending {#extending}

```{r 07-extending-001, include = F}
library(mlr3)
library(mlr3book)
```

This chapter gives instructions on how to extend `r mlr3book::mlr_pkg("mlr3")` and its extension packages with custom objects.

The approach is always the same:

1. determine the base class you want to inherit from,
1. extend the class with your custom functionality,
1. test your implementation
1. (optionally) add new object to the respective `r ref("Dictionary")`.

The chapter [Create a new learner](#extending-learners) illustrates the steps needed to create a custom learner in `r mlr3book::mlr_pkg("mlr3")`.