How do I create an empty vector of dates?

Question

Is it possible to create an empty vector of dates in r?

I can create an empty vector of integers, doubles, logicals etc:

> integer()
integer(0)
> double()
numeric(0)
> logical()
logical(0)
> length(integer())
[1] 0

but this meme doesn't work for dates, as date() returns the current system date and time. So, how would I create an emtpy vector of dates?

Check [here](http://stackoverflow.com/questions/10689055/create-an-empty-data-frame) — akrun, Jun 20 '15 at 20:00

score 19 · Answer 1 · answered Apr 04 '17 at 12:32

19

With recent versions of R, you have to supply the origin :

as.Date(x = integer(0), origin = "1970-01-01")

answered Apr 04 '17 at 12:32

PAC

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IRTFM · Accepted Answer · 2015-06-20T20:29:52.483

12

Just add a class attribute to a length-0 interger and it's a Date (at least it will appear to be one if you extend it with values that are sensible when interpreted as 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 output from as.Date happens to be a character value so the first call is a bit misleading.

> as.Date(integer())
character(0)
> str( as.Date(integer()) )
Class 'Date'  num(0) 
> dput( as.Date(integer()) )
structure(numeric(0), class = "Date")

edited Jun 20 '15 at 20:29

answered Jun 20 '15 at 20:23

IRTFM

258,963
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In my case : `> as.Date(x = integer(0))` returns an error : `Error in as.Date.numeric(x = integer(0)) : 'origin' must be supplied`. I've to supply origin : `as.Date(x = integer(0), origin = "1970-01-01")` works ! – PAC Apr 03 '17 at 10:19
1

It's not the method I demonstrated, which continues to succeed. The behavior of `as.Date(integer())` appears to have changed. It now returns the error you demonstrated. I'm unable to find an entry in the NEWS file that explains that change. – IRTFM Apr 03 '17 at 15:17

score 8 · Answer 3 · answered Dec 04 '17 at 15:38

8

Using the lubridate package and deciding what your intended format will be (eg. yyyy/mm/dd) you can use:

lubridate::ymd()
# or
lubridate::mdy()

etc.

answered Dec 04 '17 at 15:38

Dylan S.

359
4
15

score 2 · Answer 4 · answered Sep 09 '20 at 18:20

2

This appears to work and saves a few keystrokes relative to some of the other answers:

> as.Date(character(0))
Date of length 0

answered Sep 09 '20 at 18:20

gbrunick

61
2

How do I create an empty vector of dates?

4 Answers4