[R] strange date problem - May 3, 1992 is NA

[Alexander Shenkin]

On 6/22/2011 3:34 PM, Brian Diggs wrote:
> On 6/22/2011 12:09 PM, Luke Miller wrote:
>> For what it's worth, I cannot reproduce this problem under a nearly
>> identical instance of R (R 2.12.1, Win 7 Pro 64-bit). I also can't
>> reproduce the problem with R 2.13.0. You've got something truly weird
>> going on with your particular instance of R.
>>
>>
>>> is.na(strptime("5/3/1992", format="%m/%d/%Y"))
>> [1] FALSE
>>> is.na(strptime("5/2/1992", format="%m/%d/%Y"))
>> [1] FALSE
>>> sessionInfo()
>> R version 2.12.1 (2010-12-16)
>> Platform: i386-pc-mingw32/i386 (32-bit)
>>
>> locale:
>> [1] LC_COLLATE=English_United States.1252
>> [2] LC_CTYPE=English_United States.1252
>> [3] LC_MONETARY=English_United States.1252
>> [4] LC_NUMERIC=C
>> [5] LC_TIME=English_United States.1252
>>
>> attached base packages:
>> [1] stats     graphics  grDevices utils     datasets  methods   base
>>
>> other attached packages:
>> [1] rj_0.5.2-1      lattice_0.19-17
>>
>> loaded via a namespace (and not attached):
>> [1] grid_2.12.1  rJava_0.8-8  tools_2.12.1
> 
> Like Luke, I can not reproduce what you see in (an old installation of)
> R 2.12.1 (and it also didn't have rj, lattice, grid, rJava, or tools
> attached or loaded in any way).
> 
> My vague gut feeling is it might be a timezone/daylight savings time
> related issue (though usually times have to be involved).  At least,
> that is a common problem with weird things happening with dates.
> 
> What do you get as output for the following?
> 
> Sys.timezone()
> Sys.info()
> conflicts()
> dput(strptime("5/3/1992", format="%m/%d/%Y"))
> dput(as.POSIXct(strptime("5/3/1992", format="%m/%d/%Y")))
> dput(strptime("5/2/1992", format="%m/%d/%Y"))
> dput(as.POSIXct(strptime("5/2/1992", format="%m/%d/%Y")))

> Sys.timezone()
[1] "COT"
> Sys.info()
                     sysname                      release
       version                     nodename                      machine
                   "Windows"                      "7 x64" "build 7601,
Service Pack 1"             "machine_name"                        "x86"
                       login                         user
                  "username"                   "username"
> conflicts()
[1] "untangle.specials" "body<-"            "format.pval"
"round.POSIXt"      "trunc.POSIXt"      "units"
> dput(strptime("5/3/1992", format="%m/%d/%Y"))
structure(list(sec = 0, min = 0L, hour = 0L, mday = 3L, mon = 4L,
    year = 92L, wday = 0L, yday = 123L, isdst = -1L), .Names = c("sec",
"min", "hour", "mday", "mon", "year", "wday", "yday", "isdst"
), class = c("POSIXlt", "POSIXt"))
> dput(as.POSIXct(strptime("5/3/1992", format="%m/%d/%Y")))
structure(NA_real_, class = c("POSIXct", "POSIXt"), tzone = "")
> dput(strptime("5/2/1992", format="%m/%d/%Y"))
structure(list(sec = 0, min = 0L, hour = 0L, mday = 2L, mon = 4L,
    year = 92L, wday = 6L, yday = 122L, isdst = 0L), .Names = c("sec",
"min", "hour", "mday", "mon", "year", "wday", "yday", "isdst"
), class = c("POSIXlt", "POSIXt"))
> dput(as.POSIXct(strptime("5/2/1992", format="%m/%d/%Y")))
structure(704782800, class = c("POSIXct", "POSIXt"), tzone = "")


> 
> 
>> On Wed, Jun 22, 2011 at 2:40 PM, Alexander Shenkin<ashenkin at ufl.edu> 
>> wrote:
>>> On 6/22/2011 1:34 PM, Sarah Goslee wrote:
>>>> On Wed, Jun 22, 2011 at 2:28 PM, David
>>>> Winsemius<dwinsemius at comcast.net>  wrote:
>>>>>
>>>>> On Jun 22, 2011, at 2:03 PM, Sarah Goslee wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> On Wed, Jun 22, 2011 at 11:40 AM, Alexander Shenkin<ashenkin at ufl.edu>
>>>>>> wrote:
>>>>>>>>
>>>>>>>> is.na(strptime("5/2/1992", format="%m/%d/%Y"))
>>>>>>>
>>>>>>> [1] FALSE
>>>>>>>>
>>>>>>>> is.na(strptime("5/3/1992", format="%m/%d/%Y"))
>>>>>>>
>>>>>>> [1] TRUE
>>>>>>
>>>>>> I can't reproduce your problem on R 2.13.0 on linux:
>>>>>
>>>>> I also cannot reproduce it on a Mac with 2.13.0 beta
>>>>
>>>> Which strongly suggests that you should start by upgrading your R
>>>> installation if at all possible.
>>>>
>>>> I'd also recommend trying it on a default R session, with no extra
>>>> packages loaded, and no items in your workspace. It's possible that
>>>> something else is interfering.
>>>>
>>>> On linux, that's achieved by typing R --vanilla at the command line.
>>>> I'm afraid I don't know how to do it for Windows, but should be
>>>> similarly straightforward.
>>>>
>>> Thanks Sarah.  Still getting the problem.  I should surely upgrade, but
>>> still, not a bad idea to get to the bottom of this, or at least have it
>>> documented as a known issue.  BTW, I'm on Windows 7 Pro x64.
>>>
>>> (running Rgui.exe --vanilla):
>>>
>>>> is.na(strptime("5/3/1992", format="%m/%d/%Y"))
>>> [1] TRUE
>>>
>>>> is.na(strptime("5/2/1992", format="%m/%d/%Y"))
>>> [1] FALSE
>>>
>>>> sessionInfo()
>>> R version 2.12.1 (2010-12-16)
>>> Platform: i386-pc-mingw32/i386 (32-bit)
>>>
>>> locale:
>>> [1] LC_COLLATE=English_United States.1252
>>> [2] LC_CTYPE=English_United States.1252
>>> [3] LC_MONETARY=English_United States.1252
>>> [4] LC_NUMERIC=C
>>> [5] LC_TIME=English_United States.1252
>>>
>>> attached base packages:
>>> [1] stats     graphics  grDevices utils     datasets  methods   base
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>>
> 
>