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#' Sort rows using dplyr
#'
#' `step_arrange` creates a *specification* of a recipe step
#' that will sort rows using [dplyr::arrange()].
#'
#' @inheritParams step_center
#' @param ... Comma separated list of unquoted variable names.
#' Use `desc()`` to sort a variable in descending order. See
#' [dplyr::arrange()] for more details. For the `tidy`
#' method, these are not currently used.
#' @param role Not used by this step since no new variables are
#' created.
#' @param inputs Quosure of values given by `...`.
#' @return 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` which
#' contains the sorting variable(s) or expression(s). The
#' expressions are text representations and are not parsable.
#' @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). See the examples.
#' @keywords datagen
#' @concept preprocessing
#' @export
#' @examples
#' rec <- recipe( ~ ., data = iris) %>%
#' step_arrange(desc(Sepal.Length), 1/Petal.Length)
#'
#' prepped <- prep(rec, training = iris %>% slice(1:75))
#' tidy(prepped, number = 1)
#'
#' library(dplyr)
#'
#' dplyr_train <-
#' iris %>%
#' as_tibble() %>%
#' slice(1:75) %>%
#' dplyr::arrange(desc(Sepal.Length), 1/Petal.Length)
#'
#' rec_train <- bake(prepped, new_data = NULL)
#' all.equal(dplyr_train, rec_train)
#'
#' dplyr_test <-
#' iris %>%
#' as_tibble() %>%
#' slice(76:150) %>%
#' dplyr::arrange(desc(Sepal.Length), 1/Petal.Length)
#' rec_test <- bake(prepped, iris %>% slice(76:150))
#' all.equal(dplyr_test, rec_test)
#'
#' # When you have variables/expressions, you can create a
#' # list of symbols with `rlang::syms()`` and splice them in
#' # the call with `!!!`. See https://tidyeval.tidyverse.org
#'
#' sort_vars <- c("Sepal.Length", "Petal.Length")
#'
#' qq_rec <-
#' recipe( ~ ., data = iris) %>%
#' # Embed the `values` object in the call using !!!
#' step_arrange(!!!syms(sort_vars)) %>%
#' prep(training = iris)
#'
#' tidy(qq_rec, number = 1)
step_arrange <- function(
recipe, ...,
role = NA,
trained = FALSE,
inputs = NULL,
skip = FALSE,
id = rand_id("arrange")
) {
inputs <- enquos(...)
add_step(
recipe,
step_arrange_new(
terms = terms,
trained = trained,
role = role,
inputs = inputs,
skip = skip,
id = id
)
)
}
step_arrange_new <-
function(terms, role, trained, inputs, skip, id) {
step(
subclass = "arrange",
terms = terms,
role = role,
trained = trained,
inputs = inputs,
skip = skip,
id = id
)
}
#' @export
prep.step_arrange <- function(x, training, info = NULL, ...) {
step_arrange_new(
terms = x$terms,
trained = TRUE,
role = x$role,
inputs = x$inputs,
skip = x$skip,
id = x$id
)
}
#' @export
bake.step_arrange <- function(object, new_data, ...) {
dplyr::arrange(new_data, !!!object$inputs)
}
print.step_arrange <-
function(x, width = max(20, options()$width - 35), ...) {
cat("Row arrangement")
if (x$trained) {
cat(" [trained]\n")
} else {
cat("\n")
}
invisible(x)
}
#' @rdname step_arrange
#' @param x A `step_arrange` object
#' @export
tidy.step_arrange <- function(x, ...) {
cond_expr <- map(x$inputs, quo_get_expr)
cond_expr <- map_chr(cond_expr, quo_text, width = options()$width, nlines = 1)
tibble(
terms = cond_expr,
id = rep(x$id, length(x$inputs))
)
}
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