Re: [R] Convert character date time to R date-time variable.
On 08/12/2023 4:30 p.m., David Winsemius wrote:
On 12/7/23 08:21, Sorkin, John wrote:
Colleagues,
I have a matrix of character data that represents date and time. The format of
each element of the matrix is
"2020-09-17_00:00:00"
How can I convert the elements into a valid R date-time constant?
You will not be able to store these datetime values in an R matrix, at
least as class POSIXct. You could with class POSIXlt, but I've not seen
it used before but it does appear possible since matrices can contain
lists.
R matrices do no provide the capability to assign attributes, so only
atomic types and lists can be elements. If you wanted to maintain the
same structure, your first step might be to coerce to a data.frame and
then proceed, or to first construct a vector and then use as the first
argument to `matrix`.
The general sentiment is correct (it's hard to put POSIXct elements in
matrices), but it's not impossible. Almost all R objects can have
attributes.
For example,
m <- matrix(Sys.time(), 2,2)
converts the time to a numerical value, but you can view it as a POSIXlt
object using
class(m) <- c("POSIXct", class(m))
Subsetting works, e.g. m[1,1] is a time, etc.
Duncan Murdoch
Best;
David
Thank you,
John
John David Sorkin M.D., Ph.D.
Professor of Medicine, University of Maryland School of Medicine;
Associate Director for Biostatistics and Informatics, Baltimore VA Medical
Center Geriatrics Research, Education, and Clinical Center;
PI Biostatistics and Informatics Core, University of Maryland School of
Medicine Claude D. Pepper Older Americans Independence Center;
Senior Statistician University of Maryland Center for Vascular Research;
Division of Gerontology and Paliative Care,
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
Cell phone 443-418-5382
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Re: [R] Convert character date time to R date-time variable.
On 12/7/23 08:21, Sorkin, John wrote: Colleagues, I have a matrix of character data that represents date and time. The format of each element of the matrix is "2020-09-17_00:00:00" How can I convert the elements into a valid R date-time constant? You will not be able to store these datetime values in an R matrix, at least as class POSIXct. You could with class POSIXlt, but I've not seen it used before but it does appear possible since matrices can contain lists. R matrices do no provide the capability to assign attributes, so only atomic types and lists can be elements. If you wanted to maintain the same structure, your first step might be to coerce to a data.frame and then proceed, or to first construct a vector and then use as the first argument to `matrix`. Best; David Thank you, John John David Sorkin M.D., Ph.D. Professor of Medicine, University of Maryland School of Medicine; Associate Director for Biostatistics and Informatics, Baltimore VA Medical Center Geriatrics Research, Education, and Clinical Center; PI Biostatistics and Informatics Core, University of Maryland School of Medicine Claude D. Pepper Older Americans Independence Center; Senior Statistician University of Maryland Center for Vascular Research; Division of Gerontology and Paliative Care, 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 Cell phone 443-418-5382 __ R-help@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@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.
Re: [R] Convert character date time to R date-time variable.
>>>>> Ebert,Timothy Aaron
>>>>> on Thu, 7 Dec 2023 16:29:09 + writes:
> Look at the lubridate package in R. Regards, Tim
Absolutely *un*needed here !! - as others mention in this
thread.
Very simple with base R:
> strptime("2020-09-17_00:00:00", format = "%Y-%m-%d_%H:%M:%S")
[1] "2020-09-17 CEST"
>
(in my time zone).
> -Original Message- From: R-help
> On Behalf Of Sorkin, John
> Sent: Thursday, December 7, 2023 11:22 AM To:
> r-help@r-project.org (r-help@r-project.org)
> Subject: [R] Convert character date
> time to R date-time variable.
> [External Email]
> Colleagues,
> I have a matrix of character data that represents date and
> time. The format of each element of the matrix is
> "2020-09-17_00:00:00" How can I convert the elements into
> a valid R date-time constant?
> Thank you, John
> John David Sorkin M.D., Ph.D. Professor of Medicine,
> University of Maryland School of Medicine;
> Associate Director for Biostatistics and Informatics,
> Baltimore VA Medical Center Geriatrics Research,
> Education, and Clinical Center;
> PI Biostatistics and Informatics Core, University of
> Maryland School of Medicine Claude D. Pepper Older
> Americans Independence Center;
> Senior Statistician University of Maryland Center for
> Vascular Research;
> Division of Gerontology and Paliative Care, 10 North
> Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524
> Cell phone 443-418-5382
> __
> R-help@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@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.
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Re: [R] Convert character date time to R date-time variable.
`anytime` was written for this:
> anytime::anytime("2020-09-17_00:00:00")
[1] "2020-09-17 CDT"
> class(anytime::anytime("2020-09-17_00:00:00"))
[1] "POSIXct" "POSIXt"
>
Dirk
--
dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org
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Re: [R] Convert character date time to R date-time variable.
Às 16:30 de 07/12/2023, Rui Barradas escreveu:
Às 16:21 de 07/12/2023, Sorkin, John escreveu:
Colleagues,
I have a matrix of character data that represents date and time. The
format of each element of the matrix is
"2020-09-17_00:00:00"
How can I convert the elements into a valid R date-time constant?
Thank you,
John
John David Sorkin M.D., Ph.D.
Professor of Medicine, University of Maryland School of Medicine;
Associate Director for Biostatistics and Informatics, Baltimore VA
Medical Center Geriatrics Research, Education, and Clinical Center;
PI Biostatistics and Informatics Core, University of Maryland School
of Medicine Claude D. Pepper Older Americans Independence Center;
Senior Statistician University of Maryland Center for Vascular Research;
Division of Gerontology and Paliative Care,
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
Cell phone 443-418-5382
__
R-help@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.
Hello,
Coerce with ?as.POSIXct
Don't forget the underscore in the format.
as.POSIXct("2020-09-17_00:00:00", format = "%Y-%m-%d_%H:%M:%S")
Hope this helps,
Rui Barradas
Sorry, I forgot:
lubridate::ymd_hms("2020-09-17_00:00:00")
Hope this helps,
Rui Barradas
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Re: [R] Convert character date time to R date-time variable.
Às 16:21 de 07/12/2023, Sorkin, John escreveu:
Colleagues,
I have a matrix of character data that represents date and time. The format of
each element of the matrix is
"2020-09-17_00:00:00"
How can I convert the elements into a valid R date-time constant?
Thank you,
John
John David Sorkin M.D., Ph.D.
Professor of Medicine, University of Maryland School of Medicine;
Associate Director for Biostatistics and Informatics, Baltimore VA Medical
Center Geriatrics Research, Education, and Clinical Center;
PI Biostatistics and Informatics Core, University of Maryland School of
Medicine Claude D. Pepper Older Americans Independence Center;
Senior Statistician University of Maryland Center for Vascular Research;
Division of Gerontology and Paliative Care,
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
Cell phone 443-418-5382
__
R-help@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.
Hello,
Coerce with ?as.POSIXct
Don't forget the underscore in the format.
as.POSIXct("2020-09-17_00:00:00", format = "%Y-%m-%d_%H:%M:%S")
Hope this helps,
Rui Barradas
--
Este e-mail foi analisado pelo software antivírus AVG para verificar a presença
de vírus.
www.avg.com
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Re: [R] Convert character date time to R date-time variable.
Look at the lubridate package in R. Regards, Tim -Original Message- From: R-help On Behalf Of Sorkin, John Sent: Thursday, December 7, 2023 11:22 AM To: r-help@r-project.org (r-help@r-project.org) Subject: [R] Convert character date time to R date-time variable. [External Email] Colleagues, I have a matrix of character data that represents date and time. The format of each element of the matrix is "2020-09-17_00:00:00" How can I convert the elements into a valid R date-time constant? Thank you, John John David Sorkin M.D., Ph.D. Professor of Medicine, University of Maryland School of Medicine; Associate Director for Biostatistics and Informatics, Baltimore VA Medical Center Geriatrics Research, Education, and Clinical Center; PI Biostatistics and Informatics Core, University of Maryland School of Medicine Claude D. Pepper Older Americans Independence Center; Senior Statistician University of Maryland Center for Vascular Research; Division of Gerontology and Paliative Care, 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 Cell phone 443-418-5382 __ R-help@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@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] Convert character date time to R date-time variable.
Colleagues, I have a matrix of character data that represents date and time. The format of each element of the matrix is "2020-09-17_00:00:00" How can I convert the elements into a valid R date-time constant? Thank you, John John David Sorkin M.D., Ph.D. Professor of Medicine, University of Maryland School of Medicine; Associate Director for Biostatistics and Informatics, Baltimore VA Medical Center Geriatrics Research, Education, and Clinical Center; PI Biostatistics and Informatics Core, University of Maryland School of Medicine Claude D. Pepper Older Americans Independence Center; Senior Statistician University of Maryland Center for Vascular Research; Division of Gerontology and Paliative Care, 10 North Greene Street GRECC (BT/18/GR) Baltimore, MD 21201-1524 Cell phone 443-418-5382 __ R-help@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.
