Create end of the month date from a date variable

Question

I have a large data frame with date variables, which reflect first day of the month. Is there an easy way to create a new data frame date variable that represents the last d

Answer 1

A function as below would do the work (assume dt is scalar) -

month_end <- function(dt) {
    d <- seq(dt, dt+31, by="days")
    max(d[format(d,"%m")==format(dt,"%m")])
}

If you have a vector of Dates, then do the following -

sapply(dates, month_end)