Sorry, the problem has been solved. I found that strptime is a good
function for this.
DF$time2 = strptime(DF$time, format='%Y-%m-%d)
On Sat, Dec 31, 2016 at 11:02 AM, lily li <chocold12 at gmail.com> wrote:
> I tried it, but it doesn't work. The time column is blank then.
> DF$time = substring(DF$time, first=as.Date('1999-01-01),
> last=as.Date('2005-12-30'))
>
> On Sat, Dec 31, 2016 at 10:52 AM, David Winsemius <dwinsemius at comcast.net>
> wrote:
>
>>
>> > On Dec 31, 2016, at 9:26 AM, lily li <chocold12 at gmail.com> wrote:
>> >
>> > Hi all,
>> >
>> > Thanks for your help. Now I can convert data to the format "yyyy-mm-dd
>> > hh:mm:ss", but how to convert it to "yyyy-mm-dd"? The datasets are txt
>> > files, not from excel.
>>
>> Use: as.Date
>> >
>> > On Fri, Dec 30, 2016 at 3:01 PM, Duncan Mackay <dulcalma at bigpond.com>
>> wrote:
>> >
>> >> Hi
>> >>
>> >> Is this the output from Excel?
>> >> If so format it in Excel for a date format not a date-time format .
>> >> Depending how the dates were inputted into Excel and the Excel setup a
>> date
>> >> may not be a date format.
>> >> There are no rules with microsoft formatting so beware!
>> >>
>> >>
>> >> Regards
>> >>
>> >> Duncan
>> >>
>> >> Duncan Mackay
>> >> Department of Agronomy and Soil Science
>> >> University of New England
>> >> Armidale NSW 2351
>> >> Email: home: mackay at northnet.com.au
>> >>
>> >> -----Original Message-----
>> >> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of lily
>> li
>> >> Sent: Saturday, 31 December 2016 05:38
>> >> To: Rui Barradas
>> >> Cc: R mailing list
>> >> Subject: Re: [R] about data format in R
>> >>
>> >> Hi Rui,
>> >>
>> >> Thanks for your reply. When I read in data using my code, the first
>> column
>> >> ranges from 0 to 1. So when I use the code you wrote, it shows the
>> error
>> >> message:
>> >> Error in as.POSIXct.numeric(DF$Date, format = "%m/%d/%Y-%H:%M:%S") :
>> >> 'origin' must be supplied
>> >>
>> >>
>> >> On Fri, Dec 30, 2016 at 11:23 AM, Rui Barradas <ruipbarradas at sapo.pt>
>> >> wrote:
>> >>
>> >>> Hello,
>> >>>
>> >>> Have you tried
>> >>>
>> >>> df$date <- as.POSIXct(dat$date, format = "%m/%d/%Y-%H:%M:%S")
>> >>>
>> >>> ?
>> >>>
>> >>> Hope this helps,
>> >>>
>> >>> Rui Barradas
>> >>>
>> >>>
>> >>>
>> >>> Em 30-12-2016 17:40, lily li escreveu:
>> >>>
>> >>>> Hi R users,
>> >>>>
>> >>>> I'm trying to read in data, and then plot time series data. However,
>> I
>> >>>> have
>> >>>> some problems. In my dataset, the first column represents time, and
>> in
>> >> the
>> >>>> format:
>> >>>> mm/dd/yyyy-hr:min:sec; For example, 10/01/1995-00:00:00,
>> >>>> 10/01/1995-06:00:00, etc.
>> >>>>
>> >>>> df:
>> >>>> date evap precip intercept
>> >>>> 10/01/1995-00:00:00 1.5 2 0.2
>> >>>> 10/01/1995-12:00:00 1.7 2.2 0.1
>> >>>> 10/02/1995-00:00:00 1.5 1.8 0.3
>> >>>> ...
>> >>>>
>> >>>> My code is like this
>> >>>> file1 = read.table('df', head=T)
>> >>>>
>> >>>> When I read in data, I found that it read incorrectly. How to format
>> >> when
>> >>>> read in data? Thanks.
>> >>>>
>> >>>> [[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/posti
>> >>>> ng-guide.html
>> >>>> and provide commented, minimal, self-contained, reproducible code.
>> >>>>
>> >>>>
>> >>
>> >> [[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]]
>> >
>> > ______________________________________________
>> > 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/posti
>> ng-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius
>> Alameda, CA, USA
>>
>>
>
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