In Zelazny7/onx:

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
library(onx)

The onx package is built on a foundation of basic structures that describe variable transformations. These structures can be composed in interesting ways to describe how inputs map to outputs. Further, these structures are supported by a set of generic methods allowing them to be manipulated consistently and intuitively.

The basic structures in onx are Bins, Levels, and Transforms

Bins

Bins are the atomic units of transformations. A bin describes a mapping from an input to an output. The Bin class is abstract and iherited by four specialized types:

| Bin subtype | Description | Slots | |------|------------------------------------------------|---------------| | BinNumeric | Describes a left-open & right-closed range for a numeric variable | r slotNames("BinNumeric") | | BinFactor | Maps a single character input | r slotNames("BinFactor") | | BinException | Maps a single numeric input exactly | r slotNames("BinException") | | BinMissing | Maps NA values only | r slotNames("BinMissing") |

Instantiating

All of the objects in this vignette should not be used directly. The following examples aim to demonstrate how Bin objects work and should never need to directly implemented. Bins are instantiated differently depending on the type.

n <- BinNumeric(lower=0, upper=10)

f <- BinFactor(level="cat")

e <- BinException(exception=-1)

m <- BinMissing()

All bins have a show method when printed to the console:

show(n)
show(f)
show(e)
show(m)

Combining

Some bins can be combined. Testing whether two bins can be combined is done using the combinable method.

combinable(n, n)
combinable(f, f)
combinable(n, f)
combinable(n, e)
combinable(n, m)

Only BinNumeric are able to be combined. However they are only combined if their ranges overlap:

A <- BinNumeric(lower=0, upper=20)
B <- BinNumeric(lower=10, upper=30)
C <- BinNumeric(lower=25, upper=50)

combinable(A, B)
combine(A, B) ## Combines and creates a single Bin with the new range

combinable(A, C)
combine(A, C) ## returns a list of the inputs

Reduce(combine, list(A, B, C))
Reduce(combine, list(A, C, B))