Dear Anna, Rolf's explanation not withstanding, it has to do with differences in how R and Excel treat dates. If you use
as.Date(40182, origin="1899-12-30") you will get the same date as Excel. You can look at: http://office.microsoft.com/training/training.aspx?AssetID=RC102786151033&CTT=6&Origin=RP102786121033 For an official guide on how Excel dates are calculated. Apparently, Excel's calendar starts on 1 January 1900. Why one has to use an origin of 30 December 1899 in R...well, I suspect that gets back to Rolf's explanation. HTH, Josh On Thu, Mar 25, 2010 at 1:33 PM, anna <lippelann...@hotmail.com> wrote: > > Hello, I have a date value in excel: 1/4/2010 which in number format gives me > 40182. When I read this with read.xls from R I get same 40182 so what I do > is that I use the as.Date() function but here is what the as.Date() function > returns me: >> as.Date(40182) > [1] "2080-01-06" > Why don't I get the same thing as in excel? > Thanks! > > ----- > Anna Lippel > -- > View this message in context: > http://n4.nabble.com/Convert-number-to-Date-tp1691251p1691251.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@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. > -- Joshua Wiley Senior in Psychology University of California, Riverside http://www.joshuawiley.com/ ______________________________________________ R-help@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.
