Feature-engine’s variable discretisation transformers transform continuous numerical variables into discrete variables. The discrete variables will contain contiguous intervals in the case of the equal frequency and equal width transformers. The Decision Tree discretiser will return a discrete variable, in the sense that the new feature takes a finite number of values.
The following illustration shows the process of discretisation:
With discretisation, sometimes we can obtain a more homogeneous value spread from an originally skewed variable. But this is not always possible.
Discretisation plus encoding
Very often, after we discretise the numerical continuous variables into discrete intervals we want to proceed their engineering as if they were categorical. This is common practice. Throughout the user guide, we point to jupyter notebooks that showcase this functionality.