R devel - Jun 2018 - Date class shows Inf as NA; this confuses the use of is.na()

In the following example, the date class shows Inf as NA
> as_date(Inf, origin = '1970-01-01')
[1] NA

This is misleading as is.na() reports incorrectly
> is.na(as_date(Inf, origin = '1970-01-01'))
[1] FALSE

The correct approach here would probably to have an Inf (and -Inf)
*displayed* rather than NA.

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> as_date
Error: object 'as_date' not found

Must be from some not-named package...

But don't confuse the format of an object when printed with its underlying
value:
> as.Date(Inf,origin = '1970-01-01')
[1] NA
> str(as.Date(Inf,origin = '1970-01-01'))
 Date[1:1], format: NA
> as.numeric(as.Date(Inf,origin = '1970-01-01'))
[1] Inf
> is.na(Inf)
[1] FALSE
> is.na(as.Date(Inf,origin = '1970-01-01'))
[1] FALSE
> str(as.Date(27,origin = '1970-01-01'))
 Date[1:1], format: "1970-01-28"
> as.numeric(as.Date(27,origin = '1970-01-01'))
[1] 27

--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
Lab cell 925-724-7509
 
 

?On 6/8/18, 1:02 PM, "R-devel on behalf of Werner Grundlingh"
<r-devel-bounces at r-project.org on behalf of wgrundlingh at gmail.com>
wrote:

    In the following example, the date class shows Inf as NA
    
    > as_date(Inf, origin = '1970-01-01')
    [1] NA
    
    This is misleading as is.na() reports incorrectly
    
    > is.na(as_date(Inf, origin = '1970-01-01'))
    [1] FALSE
    
    The correct approach here would probably to have an Inf (and -Inf)
    *displayed* rather than NA.
    
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    ______________________________________________
    R-devel at r-project.org mailing list
    https://stat.ethz.ch/mailman/listinfo/r-devel

Indeed. as_date is from lubridate, but the same holds for as.Date.

The output and it's interpretation should be consistent, otherwise it leads
to confusion when programming. I understand that the difference exists
after asking a question on Stack Overflow:
  https://stackoverflow.com/q/50766089/914686
This understanding is never mentioned in the documentation - that an Inf
date is actually represented as NA:
  https://www.rdocumentation.org/packages/base/versions/3.5.0/topics/as.Date
So I'm of the impression that the display should be fixed as a first option
(thereby providing clarity/transparency in terms of back-end and output),
or the documentation amended (to highlight this) as a second option.

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