[Rd] as.Date without "origin"

[peter dalgaard]

This is in R-devel, mind you, i.e., unreleased and quite possibly unfinished work.

No released version of R does this. E.g.,

> as.Date(0)
Error in as.Date.numeric(0) : 'origin' must be supplied
> version
               _                                          
platform       x86_64-apple-darwin21.6.0                  
arch           x86_64                                     
os             darwin21.6.0                               
system         x86_64, darwin21.6.0                       
status         Patched                                    
major          4                                          
minor          2.2                                        
year           2022                                       
month          11                                         
day            02                                         
svn rev        83236                                      
language       R                                          
version.string R version 4.2.2 Patched (2022-11-02 r83236)
nickname       Innocent and Trusting                      


> On 2 Nov 2022, at 14:38 , Dan Dalthorp via R-devel <r-devel using 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 using 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
>>> [[alternative HTML version deleted]]
>>> 
>>> ______________________________________________
>>> R-devel using r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
> ______________________________________________
> R-devel using r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
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