as.Date without "origin"

as.Date(0)

version

On 2 Nov 2022, at 14:38 , Dan Dalthorp via R-devel <r-devel at r-project.org> wrote:

I don't see a compelling rationale for changing the default behavior as.Date to deviate from the wholly reasonable status quo of "as.Date will accept numeric data (the number of days since an epoch), but only if origin is supplied." That has been the expectation for a long, long time. 

In any case, the manual should match the behavior.

-DHD




------- Original Message -------
On Wednesday, November 2nd, 2022 at 6:20 AM, Spencer Graves <spencer.graves at prodsyse.com> wrote:

I've felt that "as.Date" should default to origin "1970-01-01", so I
added a modification to Ecfun:


Ecfun::as.Date1970(0)


If R-devel chose to change the default on this, I would happily
deprecate Ecfun::as.Date1970 in favor of base::as.Date ;-)


I would therefore support changing the documentation to match the new
behavior.


Spencer Graves


On 11/2/22 7:30 AM, Dan Dalthorp via R-devel wrote:

The new (2022-10-11 r83083 ucrt) as.Date function returns a date rather than an error when called without "origin" specified.

# previous versions of R
as.Date(0)
# Error in as.Date.numeric(0) : 'origin' must be supplied

# new:
as.Date(0)
# [1] "1970-01-01"

This is at odds with the help file, which gives:

origin

aDateobject, or something which can be coerced byas.Date(origin, ...)to such an object.

And:
as.Datewill accept numeric data (the number of days since an epoch), butonlyiforiginis supplied.

The behavior described in the help file and implemented in previous versions seems more reasonable than returning a date with an arbitrary "origin". In any case, in the r-devel there is a mismatch between the function and its description.

-Dan
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