[R] Raw epoch time from XTS

Joshua Wiley jwiley.psych at gmail.com
Sun Aug 21 21:44:14 CEST 2011


Noah,

For me xcoredata() returns a vector of the results, which makes me
wonder if you are using an old version of R or your data is somehow
stored differently.

Cheers,

Josh

On Sun, Aug 21, 2011 at 10:15 AM, Noah Silverman <noahsilverman at ucla.edu> wrote:
> Josh,
>
> Good point about including an example.
>
> calling xcoredata() does work, but only for a *single* row of the data at a time.  In R, I'm used to passing an entire data structure or vector to a function and automatically getting back a vector of all the results.  In this case, it doesn't work that way.
>
> The attr() function is probably the best solution.
>
> Thanks!
>
> --
> Noah Silverman
> UCLA Department of Statistics
> 8117 Math Sciences Building
> Los Angeles, CA 90095
>
> On Aug 20, 2011, at 1:03 AM, Joshua Wiley wrote:
>
>> Hi Noah,
>>
>> This is one of those cases where following the posting guide
>> (particularly the minimal, reproducible example part) would have
>> really helped.  Are you saying that calling:
>> xcoredata(your_xts_object) does not give you the internal
>> representation of time that you want?
>>
>> data(sample_matrix)
>> sample.xts <- as.xts(sample_matrix, descr='my new xts object')
>> # returns a list, the index is the numeric representation of time
>> displayed in the rows
>> xcoredata(sample.xts)
>>
>> You could also try the more direct:
>>
>> attr(xts_object, "index")
>>
>> If this is not what you want or is not working for you, providing us
>> the output of dput() from the first few rows of your dataset and an
>> example of what you do want would be spectacular.
>>
>> Cheers,
>>
>> Josh
>>
>> On Sat, Aug 20, 2011 at 12:44 AM, Noah Silverman <noahsilverman at ucla.edu> wrote:
>>> Hi,
>>>
>>> I have a very large data set stored as an xts object.
>>>
>>> xts is very nice about showing row labels as "human readable" dates and times.
>>>
>>> I want the actual epoch values that are stored internally.  The only way I can find to access them is one-at-a-time using the internal function: xcoredata()
>>>
>>> Calling this in an entire column, the "R" way doesn't work.  It will only return a single value.  Calling it in a loop for each row works but is painfully slow.
>>>
>>> Since the epoch is stored internally, there must be some way to just grab it as a vector.  Does anyone know how?
>>>
>>> Thanks!
>>>
>>> --
>>> Noah Silverman
>>> UCLA Department of Statistics
>>> 8117 Math Sciences Building
>>> Los Angeles, CA 90095
>>>
>>> ______________________________________________
>>> 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.
>>>
>>
>>
>>
>> --
>> Joshua Wiley
>> Ph.D. Student, Health Psychology
>> Programmer Analyst II, ATS Statistical Consulting Group
>> University of California, Los Angeles
>> https://joshuawiley.com/
>
>



-- 
Joshua Wiley
Ph.D. Student, Health Psychology
Programmer Analyst II, ATS Statistical Consulting Group
University of California, Los Angeles
https://joshuawiley.com/



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