[R] xts/zoo index problem?

David Winsemius dwinsemius at comcast.net
Tue Jan 19 17:01:55 CET 2016


> On Jan 19, 2016, at 7:44 AM, Bert Gunter <bgunter.4567 at gmail.com> wrote:
> 
> FAQ 7.31 maybe. (Unless special software is used) Only a finite number
> of numbers can be represented exactly on a computer.

Agree that seemed the likely explanation out of the gate. Here's the evidence.

> print( as.numeric(index(a), "%OS3"), digits=20)
[1] 1453137885.2300000191 1453149114.0789999962

-- 
Best;

> 
> Cheers,
> Bert
> 
> Bert Gunter
> 
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
> 
> 
> On Mon, Jan 18, 2016 at 6:26 PM, Huzefa Khalil <huzefa.khalil at umich.edu> wrote:
>> Try
>> 
>> a["2016-01-18 15:31:54.079"]
>> 
>> The question though is why R displays the milliseconds as "078", when
>> it is clearly "079"...
>> 
>> -h
>> 
>> 
>> 
>> On Mon, Jan 18, 2016 at 8:55 PM, ce <zadig_1 at excite.com> wrote:
>>> Dear all,
>>> 
>>> I have this code :
>>> 
>>> library(xts)
>>> a <- structure(c(1,2), class = c("xts", "zoo"), .indexCLASS = c("POSIXct",
>>> "POSIXt"), .indexTZ = "", tclass = c("POSIXct", "POSIXt"), tzone = "", index = structure(c(1453137885.23,
>>> 1453149114.079), tzone = "", tclass = c("POSIXct", "POSIXt")), .Dim = c(2L,
>>> 1L), .Dimnames = list(NULL, "value"))
>>> 
>>> a
>>> 
>>> a["2016-01-18 12:24:45.230"]
>>> #                    value
>>> #2016-01-18 12:24:45     1
>>> 
>>> a["2016-01-18 15:31:54.078"]
>>> #                   value
>>> 
>>> Why second line doesn't show the value? Something to do with miliseconds ?
>>> Thanks
>>> CE
>>> 
>>> ______________________________________________
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>>> and provide commented, minimal, self-contained, reproducible code.
>> 
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.

David Winsemius
Alameda, CA, USA



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