Use +
> as.Date("2001-01-01") + 45
[1] "2001-02-15"
You could also use
library(lubridate)
dmy("1/1/2001") + days(45)
R adding days to a date [duplicate]
Use +
> as.Date("2001-01-01") + 45
[1] "2001-02-15"
You could also use
library(lubridate)
dmy("1/1/2001") + days(45)