R/to-r.R

In sasquatch: Use 'SAS', R, and 'quarto' Together

#' Convert SAS table to R
#'
#' @description
#' Converts table from current SAS session into a R `data.frame`.
#'
#' @param table_name string; Name of table in SAS.
#' @param libref string; Name of libref SAS table is stored within.
#'
#' @details
#' SAS only has two data types (numeric and character). Data types are converted
#' as follows:
#'
#' * numeric -> double
#' * character -> character
#' * numeric (datetime, timezones are lost) -> POSIXct
#' * numeric (date) -> POSIXct
#'
#' In the conversion process dates and datetimes are converted to local
#' time. If utilizing another timezone, use `attr(date, "tzone") <-` or
#' `lubridate::with_tz()` to convert back to the desired time zone.
#'
#' @return `data.frame` of the specified SAS table.
#'
#' @export
#'
#' @seealso [sas_from_r()]
#' @examplesIf interactive()
#' sas_connect()
#'
#' cars <- sas_to_r("cars", "sashelp")
sas_to_r <- function(table_name, libref = "WORK") {
  check_session()
  check_string(table_name)
  check_string(libref)

  execute_if_connection_active(
    x <- .sas_to_r(table_name, libref)
  )
  x <- reticulate::py_to_r(x)

  x <- as.data.frame(lapply(x, function(col) {
    col[is.nan(col)] <- NA
    col
  }))
  date_cols <- vapply(
    x,
    \(col) inherits(col, "POSIXct"),
    FUN.VALUE = logical(1)
  )
  x[date_cols] <- lapply(x[date_cols], function(col) {
    as.POSIXct(format(col, tz = "UTC"))
  })

  x
}

.sas_to_r <- function(table_name, libref) {
  .pkgenv$session$sasdata2dataframe(table_name, libref)
}