Convert numbers to dates [duplicate]

Answer 1

Using lubridate

library(lubridate)

parse_date_time(as.character(20130107), "%Y%m%d")

If you wanted to just extract certain elements of the date, this is easy with strftime. For example, just the year:

strftime(parse_date_time(as.character(20130107), "%Y%m%d"), "%Y")