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#' Rename variables by name using dplyr
#'
#' `step_rename` creates a *specification* of a recipe step that will add
#' variables using [dplyr::rename()].
#'
#' @inheritParams step_pca
#' @inheritParams step_center
#' @param ... One or more unquoted expressions separated by commas. See
#' [dplyr::rename()] where the convention is **`new_name = old_name`**.
#' @param inputs Quosure(s) of `...`.
#' @template step-return
#' @details When an object in the user's global environment is referenced in
#' the expression defining the new variable(s), it is a good idea to use
#' quasiquotation (e.g. `!!`) to embed the value of the object in the
#' expression (to be portable between sessions).
#'
#' # Tidying
#'
#' When you [`tidy()`][tidy.recipe()] this step, a tibble with
#' columns `values` which contains the `rename` expressions as character
#' strings (and are not reparsable) is returned.
#'
#' @template case-weights-not-supported
#'
#' @family dplyr steps
#' @export
#' @examples
#' recipe(~., data = iris) %>%
#' step_rename(Sepal_Width = Sepal.Width) %>%
#' prep() %>%
#' bake(new_data = NULL) %>%
#' slice(1:5)
#'
#' vars <- c(var1 = "cyl", var2 = "am")
#' car_rec <-
#' recipe(~., data = mtcars) %>%
#' step_rename(!!vars)
#'
#' car_rec %>%
#' prep() %>%
#' bake(new_data = NULL)
#'
#' car_rec %>%
#' tidy(number = 1)
step_rename <- function(recipe, ...,
role = "predictor",
trained = FALSE,
inputs = NULL,
skip = FALSE,
id = rand_id("rename")) {
inputs <- enquos(..., .named = TRUE)
add_step(
recipe,
step_rename_new(
terms = terms,
trained = trained,
role = role,
inputs = inputs,
skip = skip,
id = id
)
)
}
step_rename_new <-
function(terms, role, trained, inputs, skip, id) {
step(
subclass = "rename",
terms = terms,
role = role,
trained = trained,
inputs = inputs,
skip = skip,
id = id
)
}
#' @export
prep.step_rename <- function(x, training, info = NULL, ...) {
step_rename_new(
terms = x$terms,
trained = TRUE,
role = x$role,
inputs = x$inputs,
skip = x$skip,
id = x$id
)
}
#' @export
bake.step_rename <- function(object, new_data, ...) {
dplyr::rename(new_data, !!!object$inputs)
}
print.step_rename <-
function(x, width = max(20, options()$width - 35), ...) {
title <- "Variable renaming for "
trained_names <- names(x$inputs)
untrained_terms <- rlang::parse_quos(
trained_names %||% "",
rlang::current_env()
)
print_step(trained_names, untrained_terms, x$trained, title, width)
invisible(x)
}
#' @rdname tidy.recipe
#' @export
tidy.step_rename <- function(x, ...) {
var_expr <- map(x$inputs, quo_get_expr)
var_expr <- map_chr(var_expr, quo_text, width = options()$width, nlines = 1)
tibble(
terms = names(x$inputs) %||% character(),
value = unname(var_expr) %||% character(),
id = rep(x$id, length(x$inputs))
)
}
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