Add/subtract 6 months (bond time) in R using lubridate

Question

I am looking to add and subtract six months reliably with lubridate.

For example, adding six months to 12/31/2014 should result in 6

Answer 1

The lubridate function %m+% may be useful here:

Add and subtract months to a date without exceeding the last day of the new month

as.Date("2014-12-31") %m+% months(6)
# [1] "2015-06-30"

To also handle the second case, you will need to round up to nearest month using ceiling_date, and subtract one day using days.

ceiling_date(as.Date("2014-02-28") %m+% months(6), unit = "month") - days(1)
# [1] "2014-08-31"