Add levels to nominal variables

step_add_levels(
  recipe,
  ...,
  role = NA,
  trained = FALSE,
  cols = NULL,
  levels = c("other", "missing"),
  skip = FALSE,
  id = rand_id("bagimpute")
)

# S3 method for step_add_levels
tidy(x, ...)

Arguments

recipe	recipe object. This step will be added
...	One or more selector functions
role	Ought to be nominal
trained	Has the recipe been prepped?
cols	columns to be prepped
levels	Factor levels to add to variables. Default = c("other", "missing")
skip	A logical. Should the step be skipped when the recipe is baked?
id	a unique step id that will be used to unprep
x	A `step_add_levels` object.

Value

Recipe with the new step

Examples

library(recipes)
d <- data.frame(num = 1:30,
                has_missing = c(rep(NA, 10), rep('b', 20)),
                has_rare = c("rare", rep("common", 29)),
                has_both = c("rare", NA, rep("common", 28)),
                has_neither = c(rep("cat1", 15), rep("cat2", 15)))
rec <- recipe( ~ ., d) %>%
  step_add_levels(all_nominal()) %>%
  prep(training = d)
baked <- bake(rec, d)
lapply(d[, sapply(d, is.factor)], levels)
#> named list()
lapply(baked[, sapply(baked, is.factor)], levels)
#> $has_missing
#> [1] "b"       "other"   "missing"
#> 
#> $has_rare
#> [1] "common"  "rare"    "other"   "missing"
#> 
#> $has_both
#> [1] "common"  "rare"    "other"   "missing"
#> 
#> $has_neither
#> [1] "cat1"    "cat2"    "other"   "missing"
#>