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

We can also use bsts::LastDayInMonth:

transform(df, date.end.month = bsts::LastDayInMonth(df$date.start.month))

#   date.start.month date.end.month
# 1       2012-01-01     2012-01-31
# 2       2012-02-01     2012-02-29
# 3       2012-03-01     2012-03-31
# 4       2012-04-01     2012-04-30