R/format_fy.R

In DFEAGILEDEVOPS/dfeR: Common DfE R tasks

#' Format financial year
#'
#' This function formats financial year variables for reporting purposes. It
#' will convert an year input from 201516 format to 2015-16 format.
#'
#' It accepts both numerical and character arguments.
#'
#' @param year Financial year
#' @return Character vector of formatted financial year
#' @family formatting functions
#' @export
#' @examples
#' format_fy(201617)
#' format_fy("201617")
format_fy <- function(year) {
  if (!grepl("^[0-9]{6,6}$", year)) {
    stop("year parameter must be a six digit number or string e.g. 201617")
  }
  sub("(.{4})(.*)", "\\1-\\2", year)
}

#' Undo financial year formatting
#'
#' This function converts financial year variables back into 201617 format.
#'
#' It accepts character arguments.
#'
#' @param year Financial year
#' @return Unformatted 6 digit year as string
#' @family formatting functions
#' @export
#' @examples
#' format_fy_reverse("2016-17")
# function to reverse the change back to e.g. 201617
format_fy_reverse <- function(year) {
  if (!grepl("^\\d{4}-\\d{2}.*", year)) {
    stop("year parameter must be a seven digit string in a financial
         year format, e.g. '2016-17'")
  }
  gsub("[^0-9A-Za-z///' ]", "", year)
}