Calculate the last day of a quarter, given year and quarter

calc_qtr_end.r

# Calculate the date of the last day of a given quarter by pasting 
# together its first day, adding three months, and subtracting a day.
# Very elegance
# Such vectorized
calc_qtr_end <- function(year, qtr) {

    require(lubridate) # Easiest way to add a month to a date

    (as.Date(paste(year, qtr * 3, "01", sep = "-")) %m+% months(1)) - 1

}