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]]
Well, one way to do it is via regex's -- no splitting and recombining needed. Note: This will convert a factor into a character vector.> z <- c("11/7/2016", "14-07-16") > z <- gsub("-([[:digit:]]{2})-([[:digit:]]{2})", "/\\1/20\\2",z) ## /\ is/ and \> z[1] "11/7/2016" "14/07/2016" I leave it to you as an exercise to either convert 7 to 07 or vice-versa if you want to do this. Note, if you have spaces sprinkled inconsistently around your separators, you'll have to work a bit harder with your regex. 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 Sat, Nov 2, 2019 at 7:25 PM <reichmanj at sbcglobal.net> wrote:> 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 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. >[[alternative HTML version deleted]]
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
?s 02:25 de 03/11/19, reichmanj at 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 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.
>
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.
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 at 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
>
> ?s 02:25 de 03/11/19, reichmanj at 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 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.
>
[[alternative HTML version deleted]]