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
