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 <chocol...@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 <dwinsem...@comcast.net> > wrote: > >> >> > On Dec 31, 2016, at 9:26 AM, lily li <chocol...@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 <dulca...@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: mac...@northnet.com.au >> >> >> >> -----Original Message----- >> >> From: R-help [mailto:r-help-boun...@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$Date, format = "%m/%d/%Y-%H:%M:%S") : >> >> 'origin' must be supplied >> >> >> >> >> >> On Fri, Dec 30, 2016 at 11:23 AM, Rui Barradas <ruipbarra...@sapo.pt> >> >> wrote: >> >> >> >>> Hello, >> >>> >> >>> Have you tried >> >>> >> >>> df$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@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@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. >> >> >> > >> > [[alternative HTML version deleted]] >> > >> > ______________________________________________ >> > 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/posti >> ng-guide.html >> > and provide commented, minimal, self-contained, reproducible code. >> >> David Winsemius >> Alameda, CA, USA >> >> > [[alternative HTML version deleted]] ______________________________________________ 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.