#' Slide over multiple inputs simultaneously
#'
#' These are variants of [slide()] that iterate over multiple inputs in
#' parallel. They are parallel in the sense that each input is processed in
#' parallel with the others, not in the sense of multicore computing. These
#' functions work similarly to `map2()` and `pmap()` from purrr.
#'
#' @inheritParams slide
#'
#' @template param-x-y
#' @template param-l
#' @template param-before-after-slide
#'
#' @return
#' A vector fulfilling the following invariants:
#'
#' \subsection{`slide2()`}{
#'
#' * `vec_size(slide2(.x, .y)) == vec_size_common(.x, .y)`
#'
#' * `vec_ptype(slide2(.x, .y)) == list()`
#'
#' }
#'
#' \subsection{`slide2_vec()` and `slide2_*()` variants}{
#'
#' * `vec_size(slide2_vec(.x, .y)) == vec_size_common(.x, .y)`
#'
#' * `vec_size(slide2_vec(.x, .y)[[1]]) == 1L`
#'
#' * `vec_ptype(slide2_vec(.x, .y, .ptype = ptype)) == ptype`
#'
#' }
#'
#' \subsection{`pslide()`}{
#'
#' * `vec_size(pslide(.l)) == vec_size_common(!!! .l)`
#'
#' * `vec_ptype(pslide(.l)) == list()`
#'
#' }
#'
#' \subsection{`pslide_vec()` and `pslide_*()` variants}{
#'
#' * `vec_size(pslide_vec(.l)) == vec_size_common(!!! .l)`
#'
#' * `vec_size(pslide_vec(.l)[[1]]) == 1L`
#'
#' * `vec_ptype(pslide_vec(.l, .ptype = ptype)) == ptype`
#'
#' }
#'
#' @examples
#' # Slide along two inputs at once
#' slide2(1:4, 5:8, ~list(.x, .y), .before = 2)
#'
#' # Or, for more than two, use `pslide()`
#' pslide(list(1:4, 5:8, 9:12), ~list(.x, .y, ..3), .before = 2)
#'
#' # You can even slide along the rows of multiple data frames of
#' # equal size at once
#' set.seed(16)
#' x <- data.frame(a = rnorm(5), b = rnorm(5))
#' y <- data.frame(c = letters[1:5], d = letters[6:10])
#'
#' row_return <- function(x_rows, y_rows) {
#' if (sum(x_rows$a) < 0) {
#' x_rows
#' } else {
#' y_rows
#' }
#' }
#'
#' slide2(x, y, row_return, .before = 1, .after = 2)
#'
#' @seealso [slide()], [slide_index2()], [hop_index2()]
#' @export
slide2 <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE) {
slide2_impl(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete,
.ptype = list(),
.constrain = FALSE,
.atomic = FALSE
)
}
#' @rdname slide2
#' @export
slide2_vec <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE,
.ptype = NULL) {
out <- slide2_impl(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete,
.ptype = list(),
.constrain = FALSE,
.atomic = TRUE
)
vec_simplify(out, .ptype)
}
slide2_vec_direct <- function(.x,
.y,
.f,
...,
.before,
.after,
.step,
.complete,
.ptype,
.slider_error_call = caller_env()) {
slide2_impl(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete,
.ptype = .ptype,
.constrain = TRUE,
.atomic = TRUE,
.slider_error_call = .slider_error_call
)
}
#' @rdname slide2
#' @export
slide2_dbl <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE) {
slide2_vec_direct(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete,
.ptype = double()
)
}
#' @rdname slide2
#' @export
slide2_int <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE) {
slide2_vec_direct(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete,
.ptype = integer()
)
}
#' @rdname slide2
#' @export
slide2_lgl <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE) {
slide2_vec_direct(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete,
.ptype = logical()
)
}
#' @rdname slide2
#' @export
slide2_chr <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE) {
slide2_vec_direct(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete,
.ptype = character()
)
}
#' @inheritParams vctrs::vec_rbind
#' @rdname slide2
#' @export
slide2_dfr <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE,
.names_to = rlang::zap(),
.name_repair = c("unique", "universal", "check_unique")) {
out <- slide2(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete
)
vec_rbind(!!!out, .names_to = .names_to, .name_repair = .name_repair)
}
#' @inheritParams vctrs::vec_cbind
#' @rdname slide2
#' @export
slide2_dfc <- function(.x,
.y,
.f,
...,
.before = 0L,
.after = 0L,
.step = 1L,
.complete = FALSE,
.size = NULL,
.name_repair = c("unique", "universal", "check_unique", "minimal")) {
out <- slide2(
.x,
.y,
.f,
...,
.before = .before,
.after = .after,
.step = .step,
.complete = .complete
)
vec_cbind(!!!out, .size = .size, .name_repair = .name_repair)
}
# ------------------------------------------------------------------------------
slide2_impl <- function(.x,
.y,
.f,
...,
.before,
.after,
.step,
.complete,
.ptype,
.constrain,
.atomic,
.slider_error_call = caller_env()) {
vec_assert(.x, call = .slider_error_call)
vec_assert(.y, call = .slider_error_call)
args <- vec_recycle_common(.x = .x, .y = .y, .call = .slider_error_call)
.f <- as_function(.f, call = .slider_error_call)
f_call <- expr(.f(.x, .y, ...))
type <- -2L
params <- list(
type,
.constrain,
.atomic,
.before,
.after,
.step,
.complete
)
slide_common(
x = args,
f_call = f_call,
ptype = .ptype,
env = environment(),
params = params
)
}
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