## -----------------------------------------------------------------------------
#| label: setup
#| include: false
knitr::opts_chunk$set(
  message = FALSE,
  digits = 3,
  collapse = TRUE,
  comment = "#>"
)
options(digits = 3)
library(recipes)


## -----------------------------------------------------------------------------
#| label: iris-base-rec
library(recipes)

# make a copy for use below
iris <- iris |> mutate(original = Species)

iris_rec <- recipe(~., data = iris)
summary(iris_rec)


## -----------------------------------------------------------------------------
#| label: iris-ref-cell
ref_cell <-
  iris_rec |>
  step_dummy(Species) |>
  prep(training = iris)
summary(ref_cell)

# Get a row for each factor level
bake(ref_cell, new_data = NULL, original, starts_with("Species")) |> distinct()


## -----------------------------------------------------------------------------
#| label: iris-helmert
# now make dummy variables with new parameterization
helmert <-
  iris_rec |>
  step_dummy(Species, contrasts = "contr.helmert") |>
  prep(training = iris)
summary(helmert)

bake(helmert, new_data = NULL, original, starts_with("Species")) |> distinct()


## -----------------------------------------------------------------------------
#| label: iris-2int
iris_int <-
  iris_rec |>
  step_interact(~ Sepal.Width:Sepal.Length) |>
  prep(training = iris)
summary(iris_int)


## -----------------------------------------------------------------------------
#| label: mm-int
model.matrix(~ Species * Sepal.Length, data = iris) |>
  as.data.frame() |>
  # show a few specific rows
  slice(c(1, 51, 101)) |>
  as.data.frame()


## -----------------------------------------------------------------------------
#| label: nope
#| eval: false
# # Must I do this?
# iris_rec |>
#   step_interact(
#     ~ Species_versicolor:Sepal.Length +
#       Species_virginica:Sepal.Length
#   )


## -----------------------------------------------------------------------------
#| label: iris-sel
iris_int <-
  iris_rec |>
  step_dummy(Species) |>
  step_interact(~ starts_with("Species"):Sepal.Length) |>
  prep(training = iris)
summary(iris_int)


## -----------------------------------------------------------------------------
#| label: sel-input
#| eval: false
# starts_with("Species")


## -----------------------------------------------------------------------------
#| label: sel-output
#| eval: false
# (Species_versicolor + Species_virginica)


## -----------------------------------------------------------------------------
#| label: int-form
iris_int


## -----------------------------------------------------------------------------
#| label: iris-dont
iris_int <-
  iris_rec |>
  step_interact(~ Species:Sepal.Length) |>
  prep(training = iris)
summary(iris_int)


## -----------------------------------------------------------------------------
#| label: one-hot
iris_rec |>
  step_dummy(Species, one_hot = TRUE) |>
  prep(training = iris) |>
  bake(original, new_data = NULL, starts_with("Species")) |>
  distinct()


## -----------------------------------------------------------------------------
#| label: one-hot-two
hot_reference <-
  iris_rec |>
  step_dummy(Species, one_hot = TRUE) |>
  prep(training = iris) |>
  bake(original, new_data = NULL, starts_with("Species")) |>
  distinct()

hot_reference

hot_helmert <-
  iris_rec |>
  step_dummy(Species, one_hot = TRUE, contrasts = "contr.helmert") |>
  prep(training = iris) |>
  bake(original, new_data = NULL, starts_with("Species")) |>
  distinct()

hot_helmert