How to account for leap years?

Question

I have some doubts about the leap years, how can I be sure that by using a formula like this

add.years= function(x,y){    
if(!isTRUE(all.equal(y,round(y))))         


        

Answer 1

You can check if a year is a leap year with leap_year from lubridate.

years <- 1895:2005
years[leap_year(years)]

This package will also handle not generating impossible 29ths of February.

ymd("2000-2-29") + years(1)    # NA
ymd("2000-2-29") %m+% years(1) # "2001-02-28"

The %m+% "add months" operator, as mentioned by @VitoshKa, rolls the date back to the end of the previous month if the actual day doesn't exist.