Our R-user's group (UC Davis) has a good post on working with dates/times in R: http://www.noamross.net/blog/2014/2/10/using-times-and-dates-in-r---presentation-code.html
On Wed, Mar 4, 2015 at 11:08 AM, David L Carlson <dcarl...@tamu.edu> wrote: > Wow! A bold prediction from someone who has done exactly zero > investigation of the basic, built-in date/time features in R. Since your > example did not include the first two digits of the year, I've used %y > instead of %Y. That will assume "19" precedes values from 69-99 and "20" > precedes values from 00 to 68. If you decide to implement this with a for > loop, it means you have much more to learn. > > > today <- "3/4/15" > > d1 <- "2/15/80" > > d2 <- "2/15/16" > > # Is d before today, if so 0, otherwise 1 > > as.integer(strptime(today, "%m/%d/%y") < strptime(d1, "%m/%d/%y")) > [1] 0 > > as.integer(strptime(today, "%m/%d/%y") < strptime(d2, "%m/%d/%y")) > [1] 1 > > ?strptime for details > > ------------------------------------- > David L Carlson > Department of Anthropology > Texas A&M University > College Station, TX 77840-4352 > > > -----Original Message----- > From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Brian > Hamel > Sent: Wednesday, March 4, 2015 8:55 AM > To: r-help@r-project.org > Subject: [R] Using dates in R > > Hi all, > > I have a dataset that includes a "date" variable. Each observation includes > a date in the form of 2/15/15, for example. I'm looking to create a new > indicator variable that is based on the date variable. So, for example, if > the date is earlier than today, I would need a "0" in the new column, and a > "1" otherwise. Note that my dataset includes dates from 1979-2012, so it is > not one-year (this means I can't easily create a new variable 1-365). > > How does R handle dates? My hunch is "not well," but perhaps there is a > package that can help me with this. Let me know if you have any > recommendations as to how this can be done relatively easily. > > Thanks! Appreciate it. > > Best, > Brian > > [[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. > -- Myfanwy Johnston Ph.D Candidate, Animal Behavior University of California at Davis Biotelemetry Lab +1.530.205.5243 [[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.
