R devel - Mar 2019 - as.Date(Inf) displays as 'NA' but is actually 'Inf'

Hi,

I think I've discovered a bug in base R.

Basically, when using 'Inf' as as 'Date', is is visually
displayed as
'NA', but R still treats it as 'Inf'. So it is very confusing to
work
with, and can easily lead to errors:

# Visually displays as NA
 > as.Date(Inf, origin="2018-01-01")
[1] NA

# Visually displays as NA
 > str(as.Date(Inf, origin="2018-01-01"))
Date[1:1], format: NA

# Is NOT NA
 > is.na(as.Date(Inf, origin="2018-01-01"))
[1] FALSE

# Is still Inf
 > is.infinite(as.Date(Inf, origin="2018-01-01"))
[1] TRUE

This gets really problematic when you are collapsing dates over groups 
and you want to find the first date of a group. Because min() returns 
Inf if there is no data:

# Visually displays as NA
 > as.Date(min(), origin="2018-01-01")
[1] NA
Warning message: In min() : no non-missing arguments to min; returning Inf

# Visually displays as NA
 > str(as.Date(min(), origin="2018-01-01"))
Date[1:1], format: NA
Warning message: In min() : no non-missing arguments to min; returning Inf

# Is not NA
 > is.na(as.Date(min(), origin="2018-01-01"))
[1] FALSE
Warning message: In min() : no non-missing arguments to min; returning Inf

# This is bad!
 > as.Date(min(), origin="2018-01-01") > "2018-01-01"
[1] TRUE
Warning message: In min() : no non-missing arguments to min; returning Inf

Here is my sessionInfo():

 > sessionInfo()
R version 3.5.0 (2018-04-23)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Debian GNU/Linux 9 (stretch)
Matrix products: default
BLAS: /usr/lib/openblas-base/libblas.so.3
LAPACK: /usr/lib/libopenblasp-r0.2.19.so

locale:
[1] LC_CTYPE=C.UTF-8 LC_NUMERIC=C LC_TIME=C.UTF-8 LC_COLLATE=C.UTF-8 
LC_MONETARY=C.UTF-8
[6] LC_MESSAGES=C LC_PAPER=C.UTF-8 LC_NAME=C LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=C.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats graphics grDevices utils datasets methods base loaded via a 
namespace (and not attached):
[1] compiler_3.5.0 tools_3.5.0 yaml_2.1.19

 > Sys.getlocale()
[1] 
"LC_CTYPE=C.UTF-8;LC_NUMERIC=C;LC_TIME=C.UTF-8;LC_COLLATE=C.UTF-8;LC_MONETARY=C.UTF-8;LC_MESSAGES=C;LC_PAPER=C.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=C.UTF-8;LC_IDENTIFICATION=C"

Richard,

Well others may chime in here, but from a mathematical point of view, the
concept of "infinite days from right now" is well-defined, so it maybe
a
"valid" date in that sense, but what day and month it will be (year
will be
Inf) are indeterminate/not well defined. Those are rightfully, NA, it
seems?

I mean you could disallow dates to take Inf at all, ever. I don't feel
strongly one way or the other about that, personally. That said, if inf
dates are allowed, its not clear to me that displaying the "Formatted"
date
string as NA, even if the value isn't,  is wrong given it can't be
determined for that "date" is. It could be displayed differently, I
suppose, but all the ones I can think of off the top of my head would be
problematic and probably break lots of formatted-dates parsing code out
there in the wild (and in R, I would guess). Things like displaying
"Inf-NA-NA", or just "Inf". Neither of those are going to
handle a
read-write round-trip well, I think.

So my personal don't-really-have-a-hat-in-the-ring opinion would be to
either leave it as is, or force as.Date(Inf, bla) to actually be NA.

Best,
~G

On Tue, Mar 5, 2019 at 12:06 PM Richard White <w at rwhite.no> wrote:
> Hi,
>
> I think I've discovered a bug in base R.
>
> Basically, when using 'Inf' as as 'Date', is is visually
displayed as
> 'NA', but R still treats it as 'Inf'. So it is very
confusing to work
> with, and can easily lead to errors:
>
> # Visually displays as NA
>  > as.Date(Inf, origin="2018-01-01")
> [1] NA
>
> # Visually displays as NA
>  > str(as.Date(Inf, origin="2018-01-01"))
> Date[1:1], format: NA
>
> # Is NOT NA
>  > is.na(as.Date(Inf, origin="2018-01-01"))
> [1] FALSE
>
> # Is still Inf
>  > is.infinite(as.Date(Inf, origin="2018-01-01"))
> [1] TRUE
>
> This gets really problematic when you are collapsing dates over groups
> and you want to find the first date of a group. Because min() returns
> Inf if there is no data:
>
> # Visually displays as NA
>  > as.Date(min(), origin="2018-01-01")
> [1] NA
> Warning message: In min() : no non-missing arguments to min; returning Inf
>
> # Visually displays as NA
>  > str(as.Date(min(), origin="2018-01-01"))
> Date[1:1], format: NA
> Warning message: In min() : no non-missing arguments to min; returning Inf
>
> # Is not NA
>  > is.na(as.Date(min(), origin="2018-01-01"))
> [1] FALSE
> Warning message: In min() : no non-missing arguments to min; returning Inf
>
> # This is bad!
>  > as.Date(min(), origin="2018-01-01") >
"2018-01-01"
> [1] TRUE
> Warning message: In min() : no non-missing arguments to min; returning Inf
>
> Here is my sessionInfo():
>
>  > sessionInfo()
> R version 3.5.0 (2018-04-23)
> Platform: x86_64-pc-linux-gnu (64-bit)
> Running under: Debian GNU/Linux 9 (stretch)
> Matrix products: default
> BLAS: /usr/lib/openblas-base/libblas.so.3
> LAPACK: /usr/lib/libopenblasp-r0.2.19.so
>
> locale:
> [1] LC_CTYPE=C.UTF-8 LC_NUMERIC=C LC_TIME=C.UTF-8 LC_COLLATE=C.UTF-8
> LC_MONETARY=C.UTF-8
> [6] LC_MESSAGES=C LC_PAPER=C.UTF-8 LC_NAME=C LC_ADDRESS=C LC_TELEPHONE=C
> [11] LC_MEASUREMENT=C.UTF-8 LC_IDENTIFICATION=C
>
> attached base packages:
> [1] stats graphics grDevices utils datasets methods base loaded via a
> namespace (and not attached):
> [1] compiler_3.5.0 tools_3.5.0 yaml_2.1.19
>
>  > Sys.getlocale()
> [1]
>
>
"LC_CTYPE=C.UTF-8;LC_NUMERIC=C;LC_TIME=C.UTF-8;LC_COLLATE=C.UTF-8;LC_MONETARY=C.UTF-8;LC_MESSAGES=C;LC_PAPER=C.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=C.UTF-8;LC_IDENTIFICATION=C"
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
	[[alternative HTML version deleted]]

format.Date runs into trouble long before Inf:
  > as.Date("2018-03-05") + c(2147466052, 2147466053)
  [1] "5881580-07-11"  "-5877641-06-23"

Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Tue, Mar 5, 2019 at 2:33 PM Gabriel Becker <gabembecker at gmail.com>
wrote:
> Richard,
>
> Well others may chime in here, but from a mathematical point of view, the
> concept of "infinite days from right now" is well-defined, so it
maybe a
> "valid" date in that sense, but what day and month it will be
(year will be
> Inf) are indeterminate/not well defined. Those are rightfully, NA, it
> seems?
>
> I mean you could disallow dates to take Inf at all, ever. I don't feel
> strongly one way or the other about that, personally. That said, if inf
> dates are allowed, its not clear to me that displaying the
"Formatted" date
> string as NA, even if the value isn't,  is wrong given it can't be
> determined for that "date" is. It could be displayed differently,
I
> suppose, but all the ones I can think of off the top of my head would be
> problematic and probably break lots of formatted-dates parsing code out
> there in the wild (and in R, I would guess). Things like displaying
> "Inf-NA-NA", or just "Inf". Neither of those are going
to handle a
> read-write round-trip well, I think.
>
> So my personal don't-really-have-a-hat-in-the-ring opinion would be to
> either leave it as is, or force as.Date(Inf, bla) to actually be NA.
>
> Best,
> ~G
>
> On Tue, Mar 5, 2019 at 12:06 PM Richard White <w at rwhite.no> wrote:
>
> > Hi,
> >
> > I think I've discovered a bug in base R.
> >
> > Basically, when using 'Inf' as as 'Date', is is
visually displayed as
> > 'NA', but R still treats it as 'Inf'. So it is very
confusing to work
> > with, and can easily lead to errors:
> >
> > # Visually displays as NA
> >  > as.Date(Inf, origin="2018-01-01")
> > [1] NA
> >
> > # Visually displays as NA
> >  > str(as.Date(Inf, origin="2018-01-01"))
> > Date[1:1], format: NA
> >
> > # Is NOT NA
> >  > is.na(as.Date(Inf, origin="2018-01-01"))
> > [1] FALSE
> >
> > # Is still Inf
> >  > is.infinite(as.Date(Inf, origin="2018-01-01"))
> > [1] TRUE
> >
> > This gets really problematic when you are collapsing dates over groups
> > and you want to find the first date of a group. Because min() returns
> > Inf if there is no data:
> >
> > # Visually displays as NA
> >  > as.Date(min(), origin="2018-01-01")
> > [1] NA
> > Warning message: In min() : no non-missing arguments to min; returning
> Inf
> >
> > # Visually displays as NA
> >  > str(as.Date(min(), origin="2018-01-01"))
> > Date[1:1], format: NA
> > Warning message: In min() : no non-missing arguments to min; returning
> Inf
> >
> > # Is not NA
> >  > is.na(as.Date(min(), origin="2018-01-01"))
> > [1] FALSE
> > Warning message: In min() : no non-missing arguments to min; returning
> Inf
> >
> > # This is bad!
> >  > as.Date(min(), origin="2018-01-01") >
"2018-01-01"
> > [1] TRUE
> > Warning message: In min() : no non-missing arguments to min; returning
> Inf
> >
> > Here is my sessionInfo():
> >
> >  > sessionInfo()
> > R version 3.5.0 (2018-04-23)
> > Platform: x86_64-pc-linux-gnu (64-bit)
> > Running under: Debian GNU/Linux 9 (stretch)
> > Matrix products: default
> > BLAS: /usr/lib/openblas-base/libblas.so.3
> > LAPACK: /usr/lib/libopenblasp-r0.2.19.so
> >
> > locale:
> > [1] LC_CTYPE=C.UTF-8 LC_NUMERIC=C LC_TIME=C.UTF-8 LC_COLLATE=C.UTF-8
> > LC_MONETARY=C.UTF-8
> > [6] LC_MESSAGES=C LC_PAPER=C.UTF-8 LC_NAME=C LC_ADDRESS=C
LC_TELEPHONE=C
> > [11] LC_MEASUREMENT=C.UTF-8 LC_IDENTIFICATION=C
> >
> > attached base packages:
> > [1] stats graphics grDevices utils datasets methods base loaded via a
> > namespace (and not attached):
> > [1] compiler_3.5.0 tools_3.5.0 yaml_2.1.19
> >
> >  > Sys.getlocale()
> > [1]
> >
> >
>
"LC_CTYPE=C.UTF-8;LC_NUMERIC=C;LC_TIME=C.UTF-8;LC_COLLATE=C.UTF-8;LC_MONETARY=C.UTF-8;LC_MESSAGES=C;LC_PAPER=C.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=C.UTF-8;LC_IDENTIFICATION=C"
> >
> > ______________________________________________
> > R-devel at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
> >
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
	[[alternative HTML version deleted]]

Hi Gabriel,

The point is that it *visually* displays as NA, but is.na() still 
responds as FALSE.

When I (and I am sure many people) see an NA, we then use is.na(). If we 
see Inf displayed, we then use is.infinite(). With as.Date() this breaks 
down.

I'm not arguing that as.Date(Inf) should be coerced to NA. I'm arguing 
that as.Date(Inf) should be *visually* displayed as Inf (i.e. the 
truth!). I doubt this would break any existing code, because 
as.Date(Inf) acts as Inf in every way possible, except for when you 
visually look at the output printed on the screen.

William - For all the other Date bugs, they don't visually display false 
information about the variable's contents. They might give wrong output, 
but the output displayed is what exists inside the variable.

If we can't trust the R console to display the truth, then we are in a 
lot of trouble.

 > a <- as.Date(Inf, origin="2018-01-01")
 > a
[1] NA
 > is.na(a)
[1] FALSE

Richard

Gabriel Becker wrote on 06/03/2019 00:33:
> Richard,
>
> Well others may chime in here, but from a mathematical point of view, 
> the concept of "infinite days from right now" is well-defined, so
it
> maybe a "valid" date in that sense, but what day and month it
will be
> (year will be Inf) are indeterminate/not well defined. Those are 
> rightfully, NA, it seems?
>
> I mean you could disallow dates to take Inf at all, ever. I don't feel 
> strongly one way or the other about that, personally. That said, if 
> inf dates are allowed, its not clear to me that displaying the 
> "Formatted" date string as NA, even if the value isn't,? is
wrong
> given it can't be determined for that "date" is. It could be
displayed
> differently, I suppose, but all the ones I can think of off the top of 
> my head would be problematic and probably break lots of 
> formatted-dates parsing code out there in the wild (and in R, I would 
> guess). Things like displaying "Inf-NA-NA", or just
"Inf". Neither of
> those are going to handle a read-write round-trip well, I think.
>
> So my personal don't-really-have-a-hat-in-the-ring opinion would be to 
> either leave it as is, or force as.Date(Inf, bla) to actually be NA.
>
> Best,
> ~G
>
> On Tue, Mar 5, 2019 at 12:06 PM Richard White <w at rwhite.no 
> <mailto:w at rwhite.no>> wrote:
>
>     Hi,
>
>     I think I've discovered a bug in base R.
>
>     Basically, when using 'Inf' as as 'Date', is is
visually displayed as
>     'NA', but R still treats it as 'Inf'. So it is very
confusing to work
>     with, and can easily lead to errors:
>
>     # Visually displays as NA
>     ?> as.Date(Inf, origin="2018-01-01")
>     [1] NA
>
>     # Visually displays as NA
>     ?> str(as.Date(Inf, origin="2018-01-01"))
>     Date[1:1], format: NA
>
>     # Is NOT NA
>     ?> is.na <http://is.na>(as.Date(Inf,
origin="2018-01-01"))
>     [1] FALSE
>
>     # Is still Inf
>     ?> is.infinite(as.Date(Inf, origin="2018-01-01"))
>     [1] TRUE
>
>     This gets really problematic when you are collapsing dates over
>     groups
>     and you want to find the first date of a group. Because min() returns
>     Inf if there is no data:
>
>     # Visually displays as NA
>     ?> as.Date(min(), origin="2018-01-01")
>     [1] NA
>     Warning message: In min() : no non-missing arguments to min;
>     returning Inf
>
>     # Visually displays as NA
>     ?> str(as.Date(min(), origin="2018-01-01"))
>     Date[1:1], format: NA
>     Warning message: In min() : no non-missing arguments to min;
>     returning Inf
>
>     # Is not NA
>     ?> is.na <http://is.na>(as.Date(min(),
origin="2018-01-01"))
>     [1] FALSE
>     Warning message: In min() : no non-missing arguments to min;
>     returning Inf
>
>     # This is bad!
>     ?> as.Date(min(), origin="2018-01-01") >
"2018-01-01"
>     [1] TRUE
>     Warning message: In min() : no non-missing arguments to min;
>     returning Inf
>
>     Here is my sessionInfo():
>
>     ?> sessionInfo()
>     R version 3.5.0 (2018-04-23)
>     Platform: x86_64-pc-linux-gnu (64-bit)
>     Running under: Debian GNU/Linux 9 (stretch)
>     Matrix products: default
>     BLAS: /usr/lib/openblas-base/libblas.so.3
>     LAPACK: /usr/lib/libopenblasp-r0.2.19.so
>     <http://libopenblasp-r0.2.19.so>
>
>     locale:
>     [1] LC_CTYPE=C.UTF-8 LC_NUMERIC=C LC_TIME=C.UTF-8 LC_COLLATE=C.UTF-8
>     LC_MONETARY=C.UTF-8
>     [6] LC_MESSAGES=C LC_PAPER=C.UTF-8 LC_NAME=C LC_ADDRESS=C
>     LC_TELEPHONE=C
>     [11] LC_MEASUREMENT=C.UTF-8 LC_IDENTIFICATION=C
>
>     attached base packages:
>     [1] stats graphics grDevices utils datasets methods base loaded via a
>     namespace (and not attached):
>     [1] compiler_3.5.0 tools_3.5.0 yaml_2.1.19
>
>     ?> Sys.getlocale()
>     [1]
>    
"LC_CTYPE=C.UTF-8;LC_NUMERIC=C;LC_TIME=C.UTF-8;LC_COLLATE=C.UTF-8;LC_MONETARY=C.UTF-8;LC_MESSAGES=C;LC_PAPER=C.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=C.UTF-8;LC_IDENTIFICATION=C"
>
>     ______________________________________________
>     R-devel at r-project.org <mailto:R-devel at r-project.org>
mailing list
>     https://stat.ethz.ch/mailman/listinfo/r-devel
>

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