R: Convert Strings to Factors

step_string2factor {recipes}

R Documentation

Convert Strings to Factors

Description

step_string2factor will convert one or more character vectors to factors (ordered or unordered).

Usage

step_string2factor(recipe, ..., role = NA, trained = FALSE, levels = NULL,
  ordered = FALSE, skip = FALSE)

## S3 method for class 'step_string2factor'
tidy(x, ...)

Arguments

`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 will converted to factors. See `selections()` for more details. For the `tidy` method, these are not currently used.
`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.
`levels`	An options specification of the levels to be used for the new factor. If left `NULL`, the sorted unique values present when `bake` is called will be used.
`ordered`	A single logical value; should the factor(s) be ordered?
`skip`	A logical. Should the step be skipped when the recipe is baked by `bake.recipe()`? While all operations are baked when `prep.recipe()` is run, some operations may not be able to be conducted on new data (e.g. processing the outcome variable(s)). Care should be taken when using `skip = TRUE` as it may affect the computations for subsequent operations
`x`	A `step_string2factor` object.

Details

If levels is given, step_string2factor will convert all factors to have the same levels. Also, note that prep has an option stringsAsFactors that defaults to TRUE. This should be changed so that raw character data will be applied to step_string2factor.

Value

An updated version of recipe with the new step added to the sequence of existing steps (if any). For the tidy method, a tibble with columns terms (the selectors or variables selected) and ordered.

Examples

data(okc)

rec <- recipe(~ diet + location, data = okc)

make_factor <- rec %>%
  step_string2factor(diet)
make_factor <- prep(make_factor,
                    training = okc,
                    stringsAsFactors = FALSE,
                    retain = TRUE)

# note that `diet` is a factor
juice(make_factor) %>% head
okc %>% head
tidy(make_factor, number = 1)

[Package recipes version 0.1.3 Index]