[R] transforming dates

[Bert Gunter]

Yes, indeed.

Thanks, David.

Cheers,
Bert

On Sun, Nov 3, 2019 at 12:22 PM David Winsemius <dwinsemius using comcast.net>
wrote:

>
> On 11/3/19 11:51 AM, Bert Gunter wrote:
> > Rui is right -- lubridate functionality and robustness is better -- but
> > just for fun, here is a simple function, poorly named reformat(), that
> > splits up the date formats, cleans them up and standardizes them a bit,
> and
> > spits them back out with a sep character of your choice (your original
> > split and recombine suggestion). Lubridate probably does something
> similar
> > but more sophisticated, but maybe it's worthwhile to see how one can do
> it
> > using basic functionality. This only requires a few short lines of code.
>
> If one wants to investigate existing efforts at automatic date _and_
> time reformatting, then do not forget Dirk's anytime package:
>
>
> https://cran.r-project.org/web/packages/anytime/index.html
>
>
> --
>
> David.
>
> >
> > reformat <- function(z, sep = "-"){
> >     z <- gsub(" ","",z) ## remove blanks
> >     ## break up dates into 3 component pieces and convert to matrix
> >     z <- matrix(unlist(strsplit(z, "-|/")), nrow = 3)
> >     ## add "0" in front of single digit in dd and mm
> >     ## add "20" in front  of "yy"
> >     for(i in 1:2) z[i, ] <- gsub("\\<([[:digit:]])\\>","0\\1",z[i, ])
> >     z[3, ] <- sub("\\<([[:digit:]]{2})\\>","20\\1",z[3, ])
> >     ## combine back into single string separated by sep
> >     paste(z[1, ],z[2, ],z[3, ], sep = sep)
> > }
> >
> > ## Testit
> >> z <- c(" 1 / 22 /2015"," 1 -5 -15","11/7/2016", "14-07-16")
> >> reformat(z)
> > [1] "01-22-2015" "01-05-2015" "11-07-2016" "14-07-2016"
> >
> >> reformat(z,"/")
> > [1] "01/22/2015" "01/05/2015" "11/07/2016" "14/07/2016"
> >
> > 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 Sun, Nov 3, 2019 at 12:15 AM Rui Barradas <ruipbarradas using sapo.pt>
> wrote:
> >
> >> Hello,
> >>
> >> I believe the simplest is to use package lubridate. Its functions try
> >> several formats until either one is right or none fits the data.
> >>
> >> x <- c('11/7/2016', '14-07-16')
> >> lubridate::dmy(x)
> >> #[1] "2016-07-11" "2016-07-14"
> >>
> >>
> >> The order dmy must be the same for all vector elements, if not
> >>
> >> y <- c('11/7/2016', '14-07-16', '2016/7/11')
> >> lubridate::dmy(y)
> >> #[1] "2016-07-11" "2016-07-14" NA
> >> #Warning message:
> >> # 1 failed to parse.
> >>
> >>
> >> Hope this helps,
> >>
> >> Rui Barradas
> >>
> >> Às 02:25 de 03/11/19, reichmanj using sbcglobal.net escreveu:
> >>> R-Help Forum
> >>>
> >>>
> >>>
> >>> I have a data set that contains a date field but the dates are in two
> >>> formats
> >>>
> >>>
> >>>
> >>> 11/7/2016            dd/mm/yyyy
> >>>
> >>> 14-07-16               dd-mm-yy
> >>>
> >>>
> >>>
> >>> How would I go about correcting this problem. Should I separate the
> >> dates,
> >>> format them , and then recombine?
> >>>
> >>>
> >>>
> >>> Sincerely
> >>>
> >>>
> >>>
> >>> Jeff Reichman
> >>>
> >>> (314) 457-1966
> >>>
> >>>
> >>>
> >>>
> >>>        [[alternative HTML version deleted]]
> >>>
> >>> ______________________________________________
> >>> R-help using 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 using 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.
> >>
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help using 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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