R/age_in_years.R

In epicentre-msf/llutils: Linelist Utilities

#' Convert vectors of ages to units of years
#'
#' @param age Vector of age values (numeric)
#' @param age_unit Vector of age units ("Year(s)", "Month(s)", "Week(s)",
#'   "Day(s)", or \<NA\> (case-insensitive))
#'
#' @return
#' A numeric vector of ages in years
#'
#' @examples
#' ages <- c(70, 3, 53, 61, 20, 9)
#' units <- c("Years", "Weeks", "Years", "Years", "Months", "Months")
#'
#' age_in_years(ages, units)
#'
#' @export age_in_years
age_in_years <- function(age, age_unit) {

  age_unit <- tolower(age_unit)
  age_unit <- gsub("[Ss]$", "", age_unit) # remove plural

  valid_units <- c("year", "month", "week", "day", NA_character_)
  if (!all(age_unit %in% valid_units)) {
    warning("age_unit must be 'Year(s)', 'Month(s)', 'Week(s)', 'Day(s)', or ",
            "<NA> (case-insensitive)")
  }

  mapply(age_in_years_, age, age_unit)
}



#' @noRd
age_in_years_ <- function(age, age_unit) {
  switch(
    age_unit,
    "year" = age,
    "month" = age / 12.0,
    "week" = age / 52.17857,
    "day" = age / 365.25,
    age
  )
}