How do I create an empty vector of dates?
Is it possible to create an empty vector of dates in r?
I can create an empty vector of integers, paired, boolean, etc .:
> integer()
integer(0)
> double()
numeric(0)
> logical()
logical(0)
> length(integer())
[1] 0
but this meme does not work for dates as it date()
returns the current system date and time. So how can I create an emtpy vector of dates?
Just add the class attribute to the time interval -0 and date (at least it will show up as one if you extend it with values that are reasonable when interpreting R-Dates):
> x <- integer(0)
> x
integer(0)
> class(x) <- "Date"
> x
character(0)
> class(x)
[1] "Date"
> y <- c(x, 1400)
> y
[1] "1973-11-01"
The exit as.Date
turns out to be a symbolic value, so the first call is a little misleading.
> as.Date(integer())
character(0)
> str( as.Date(integer()) )
Class 'Date' num(0)
> dput( as.Date(integer()) )
structure(numeric(0), class = "Date")
In recent versions of R, you need to provide the source:
as.Date(x = integer(0), origin = "1970-01-01")
Using the lubridate package and having determined what your intended format will be (e.g. yyyy / mm / dd), you can use:
lubridate::ymd()
# or
lubridate::mdy()
and etc.