R/future-imap.R

In furrr: Apply Mapping Functions in Parallel using Futures

#' Apply a function to each element of a vector, and its index via futures
#'
#' These functions work the same as [purrr::imap()] functions,
#' but allow you to map in parallel.
#'
#' @param .f A function, specified in one of the following ways:
#'
#'   * A named function, e.g. `paste`.
#'   * An anonymous function, e.g. `\(x, idx) x + idx` or
#'     `function(x, idx) x + idx`.
#'   * A formula, e.g. `~ .x + .y`. Use `.x` to refer to the current element and
#'     `.y` to refer to the current index. No longer recommended.
#'
#' @inheritParams future_map
#'
#' @return
#' A vector the same length as .x.
#'
#' @export
#' @examples
#' \donttest{plan(multisession, workers = 2)}
#'
#' future_imap_chr(sample(10), ~ paste0(.y, ": ", .x))
#'
#' \dontshow{
#' # Close open connections for R CMD Check
#' if (!inherits(plan(), "sequential")) plan(sequential)
#' }
future_imap <- function(
  .x,
  .f,
  ...,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}

#' @rdname future_imap
#' @export
future_imap_chr <- function(
  .x,
  .f,
  ...,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2_chr(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}

#' @rdname future_imap
#' @export
future_imap_dbl <- function(
  .x,
  .f,
  ...,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2_dbl(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}

#' @rdname future_imap
#' @export
future_imap_int <- function(
  .x,
  .f,
  ...,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2_int(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}

#' @rdname future_imap
#' @export
future_imap_lgl <- function(
  .x,
  .f,
  ...,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2_lgl(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}

#' @rdname future_imap
#' @export
future_imap_vec <- function(
  .x,
  .f,
  ...,
  .ptype = NULL,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2_vec(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .ptype = .ptype,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}

#' @rdname future_imap
#' @export
future_imap_dfr <- function(
  .x,
  .f,
  ...,
  .id = NULL,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2_dfr(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .id = .id,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}

#' @rdname future_imap
#' @export
future_imap_dfc <- function(
  .x,
  .f,
  ...,
  .options = furrr_options(),
  .env_globals = parent.frame(),
  .progress = FALSE
) {
  future_map2_dfc(
    .x = .x,
    .y = vec_index(.x),
    .f = .f,
    ...,
    .options = .options,
    .env_globals = .env_globals,
    .progress = .progress
  )
}