This is a way to stick within the POSIXct
universe of lubridate
and not change date formats to base R's POSIXt
. I avoid changing the date format in my scripts because I find it is a common place where bugs (for example time-zone changes or losing timestamps) are introduced. It follows this advice to use %m+%
: R: adding 1 month to a date
# example date is a leap day for a "worst case scenario"
library("lubridate")
posixct.in <- parse_date_time(x = "2016-02-29", orders = "ymd")
# [1] "2016-02-29 UTC"
posixct.seq <- posixct.in %m+% years(x = seq.int(from = 0, to = 3, by = 1))
# [1] "2016-02-29 UTC" "2017-02-28 UTC" "2018-02-28 UTC" "2019-02-28 UTC"
posixct.seq <- posixct.in %m+% months(x = seq.int(from = 0, to = 3, by = 1))
# [1] "2016-02-29 UTC" "2016-03-29 UTC" "2016-04-29 UTC" "2016-05-29 UTC"
posixct.seq <- posixct.in %m+% days(x = seq.int(from = 0, to = 3, by = 1))
# [1] "2016-02-29 UTC" "2016-03-01 UTC" "2016-03-02 UTC" "2016-03-03 UTC"
posixct.seq <- posixct.in %m+% weeks(x = seq.int(from = 0, to = 3, by = 1))
# [1] "2016-02-29 UTC" "2016-03-07 UTC" "2016-03-14 UTC" "2016-03-21 UTC"
A regular +
also works sometimes, but the %m+%
prevents errors like this:
posixct.seq <- posixct.in + years(x = seq.int(from = 0, to = 3, by = 1))
# [1] "2016-02-29 UTC" NA NA NA
At first I was confused because I thought %m+
was just a way to add months, and similar lubridate
commands like %y+%
etc. do not exist. But, turns out the "m" doesn't stand for "month addition". My best guess is "magic" =)