R/dt_fst.R

In vigicaen: 'VigiBase' Pharmacovigilance Database Toolbox

#' Read fst and convert to data.table
#'
#' @description `r lifecycle::badge('deprecated')` Short hand to `as.data.table(read_fst())`.
#' File extension can be omitted.
#'
#' @details Output is a data.table.
#' The function is deprecated, with the use of parquet tables. Tables can now
#' be loaded **IN**-memory or **OUT** of memory with \code{\link{dt_parquet}}.
#'
#' @param path_base A character string, providing the path to read from.
#' @param name A character string, the file name.
#' @param ext A character string, optional, specifying the file extension.
#' @keywords import
#' @export
#' @returns A data.table, read from `path_base/(name)`.
#' @seealso [dt_parquet()], [tb_vigibase()], [tb_who()], [tb_meddra()]
#' @examples
#'
#' # Say you have a data.frame stored in an fst format, such as this one
#' df <- data.frame(a = 1:10)
#'
#' path <- paste0(tempdir(), "/dtfstex")
#' dir.create(path)
#'
#' fst::write_fst(x = df,
#'               path = paste0(path, "/", "df.fst")
#'               )
#' # Now you have a new session without df.
#' rm(df)
#'
#' # You may import the file directly to data.table format with dt_fst
#' df <- dt_fst(path, "df")
#'
#' # Clean up (required for CRAN checks)
#' unlink(path, recursive = TRUE)

dt_fst <- function(path_base,
                   name = NULL,
                   ext = ".fst"){

  lifecycle::deprecate_warn("0.12.0", "dt_fst()", "dt_parquet()")

  ext <-
    if(!is.null(name) && !grepl(".fst$", name, perl = TRUE)) {
      ext
    } else if(is.null(name) && !grepl(".fst$", path_base, perl = TRUE)){
      ext
    }

  # helps working with the "here" package, or tempdir

  if(!is.null(name) && !grepl("(/|\\\\)$", path_base, perl = TRUE)){
    path_base <-
      paste0(path_base, "/")
  }

  path <- paste0(path_base, name, ext)
  data.table::as.data.table(fst::read_fst(path))
}