format(ISOdate(2012,1:12,1),"%b-%Y") [1] "Jan-2012" "Feb-2012" "Mar-2012" "Apr-2012" "May-2012" "Jun-2012" [7] "Jul-2012" "Aug-2012" "Sep-2012" "Oct-2012" "Nov-2012" "Dec-2012"
First of the month is just as clean, and AFAIR they all have a first ;-) Jeff On Tue, Jan 31, 2012 at 2:37 PM, Dirk Eddelbuettel <e...@debian.org> wrote: > > On 31 January 2012 at 15:17, Duncan Murdoch wrote: > | On 12-01-31 2:56 PM, Dirk Eddelbuettel wrote: > | > > | > R> seq(as.Date(Sys.Date()), by="-1 months", length=6) > | > [1] "2012-01-31" "2011-12-31" "2011-12-01" "2011-10-31" "2011-10-01" > "2011-08-31" > | > R> > | > > | > Notice how October appears twice. > | > | > > | > Now, date arithmetic is gruesome but the documentation for seq.Date et al > | > does not hint it wouldn't honour the by= argument. So a bug, or merely a > | > somewhat less than desirable features. > | > | It is giving you Jan 31, Dec 31, Nov 31, Oct 31, Sep 31, Aug 31 -- > | except some of those months don't have 31 days, so it is converting > | those dates to ones that really exist. (This is documented in ?seq.POSIXt.) > | > | Isn't this what you asked for? > > No as I was feeding this into format(..., "%b-%y") to create 'pretty' names, > and the double entries screw that. > > Morale: pick a mid-month date, and shift that. > > Dirk > > | Duncan Murdoch > | > | > | > > | > (And yes, I think I know that Hadley's lubridate has code for this too, > but > | > so may my RcppBDT which is sitting on top of Boost::DateTime code ...) > | > > | > Dirk > | > > | > > -- > "Outside of a dog, a book is a man's best friend. Inside of a dog, it is too > dark to read." -- Groucho Marx > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Jeffrey Ryan jeffrey.r...@lemnica.com www.lemnica.com www.esotericR.com R/Finance 2012: Applied Finance with R www.RinFinance.com See you in Chicago!!!! ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
