R/daysOfMonth.R

In Sumpfohreule/MyUtilities: Collection of general functions which are useful in multiple contexts

#' Calculating the number of days of a given date
#'
#' @description This function calculates the number of days of a month, based on
#' a given POSIXct value.
#' Leap years should be handled correctly.
#'
#' @param date A single POSIXct value for which the number of days should be
#' calculated
#' @keywords dates
#' @export
#' @examples
#' # febuary of a leap year (29 days)
#' daysOfMonth(as.POSIXctFixed("2016-02-01", tz = "UTC"))
#'
#' # febuary of a non leap year
#' daysOfMonth(as.POSIXctFixed("2017-02-01", tz = "UTC"))
#'
daysOfMonth <- function(date) {
  .Deprecated("lubridate::days_in_month")
  year <- data.table::year(date)
  month <- data.table::month(date)
  start <- as.POSIXctFixed(paste0(year, "-", month, "-01"),
    format = "%Y-%m-%d",
    tz = "UTC"
  )
  end <- as.POSIXctFixed(paste0(year, "-", month + 1, "-01"),
    format = "%Y-%m-%d", tz = "UTC"
  )
  return(as.integer(end - start))
}