step_ordinalscore {recipes} | R Documentation |
step_ordinalscore
creates a specification of a recipe step that
will convert ordinal factor variables into numeric scores.
step_ordinalscore(recipe, ..., role = NA, trained = FALSE, columns = NULL, convert = as.numeric)
recipe |
A recipe object. The step will be added to the sequence of operations for this recipe. |
... |
One or more selector functions to choose which variables are
affected by the step. See |
role |
Not used by this step since no new variables are created. |
trained |
A logical to indicate if the quantities for preprocessing have been estimated. |
columns |
A character string of variables that will be converted. This is |
convert |
A function that takes an ordinal factor vector as an input and outputs a single numeric variable. |
Dummy variables from ordered factors with C
levels will create polynomial basis functions with C-1
terms. As an alternative, this step can be used to translate the ordered levels into a single numeric vector of values that represent (subjective) scores. By default, the translation uses a linear scale (1, 2, 3, ... C
) but custom score functions can also be used (see the example below).
An updated version of recipe
with the
new step added to the sequence of existing steps (if any).
fail_lvls <- c("meh", "annoying", "really_bad") ord_data <- data.frame(item = c("paperclip", "twitter", "airbag"), fail_severity = factor(fail_lvls, levels = fail_lvls, ordered = TRUE)) model.matrix(~fail_severity, data = ord_data) linear_values <- recipe(~ item + fail_severity, data = ord_data) %>% step_dummy(item) %>% step_ordinalscore(fail_severity) linear_values <- prep(linear_values, training = ord_data, retain = TRUE) juice(linear_values, everything()) custom <- function(x) { new_values <- c(1, 3, 7) new_values[as.numeric(x)] } nonlin_scores <- recipe(~ item + fail_severity, data = ord_data) %>% step_dummy(item) %>% step_ordinalscore(fail_severity, convert = custom) nonlin_scores <- prep(nonlin_scores, training = ord_data, retain = TRUE) juice(nonlin_scores, everything())