get_age.R

#' @name get_age
#'
#' @title
#' Calculates ages
#'
#' @description
#' Calculates the age of individuals at a given date,
#' based on their date of birth. This uses \code{\link{lubridate}} functions
#' to calculate an age, which means that leap years are also taken into account.
#'
#' @export
#'
#' @param DOB
#' vector of \code{Date} objects to be used as the date of
#' birth
#'
#' @param Date
#' vector of \code{Date} objects to be used as the date at
#' which the age is requested
#'
#' @examples
#' birthdays <- lubridate::dmy(c("01/01/1990", "29/02/1992", "31/12/2000", "15/06/1995"))
#' get_age(birthdays, lubridate::today())
get_age <- function(DOB, Date) {
  requireNamespace("lubridate", quietly = T)
  dT.int <- lubridate::interval(DOB, Date)
  dT.length <- lubridate::time_length(dT.int, unit = "year")
  return(floor(dT.length))
}