Comparing two date columns
On Feb 21, 2010, at 2:19 PM, Newbie19_02 wrote:
Hi everyone, I have another fairly simple question. I want to take the earliest of two dates from these two date columns. I've tried converting the dates to numbers and just get a vector full of NA's. I've also tried using the chron function to compare the two and have been unsuccessful. I then tried to use:temp.2 <- as.POSIXct(strptime(temp, '%d/%m/%Y')) where temp is character vector of one of the date columns this did not work either. I'm not sure what to do now. date_1 date_2 2005-11-25 <NA> 2007-10-23 <NA> <NA> 1999-12-13 2006-01-25 <NA> 2006-06-12 <NA> 2005-08-08 <NA> 2007-12-12 <NA> 2008-04-29 <NA> 2005-03-28 <NA> 2004-11-18 2000-11-02 2006-03-16 <NA> 2007-01-17 <NA>
We cannot tell from that output what data type you are working with.
You may not be working with Dates at all. You also have not offered
the code that is not working. If they are dates, then pmin should work
well.
> pmin(as.Date("2004-11-18"), as.Date("2000-11-02"))
[1] "2000-11-02"
Next time use dput to allow unambiguous communication. (The fact that
you are not using either dput or dump suggests you have not yet spent
enough effort at reading the Posting Guide.)
David > > > Thanks for your help, > Natalie > -- > View this message in context: http://n4.nabble.com/Comparing-two-date-columns-tp1563776p1563776.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at r-project.org mailing list > 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.