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Require Factor Levels

Source: R/require-sets.R
require_levels.Rd

Compares levels(value) of a factor with a reference. The classic predict(newdata) failure, a factor with a level the model has not seen, is require_levels(levels(train$f), mode = "subset").

Usage

require_levels(
  restriction,
  levels,
  mode = c("identical", "subset", "superset")
)

Arguments

restriction

a restriction object.

levels

character vector of reference levels.

mode

how the observed levels relate to levels:

  • "identical": the same levels in the same order;

  • "subset": every observed level is in levels;

  • "superset": every level in levels is present.

Value

The modified restriction object.

Details

The levels of the factor are compared, whether or not a level occurs in the data. Non-factor input fails with a type error.

See also

Other value checks: require_between(), require_contains(), require_disjoint(), require_negative(), require_one_of(), require_positive(), require_set_equal(), require_unique()

Examples

f_v <- restrict("f") |> require_levels(c("a", "b"), mode = "subset")
f_v(factor(c("a", "b")))
try(f_v(factor(c("a", "z"))))
#> Error : f: unexpected level: "z"