seq.Date bug?
-----Original Message----- From: r-devel-bounces at r-project.org [mailto:r-devel-bounces at r-project.org] On Behalf Of Jeffrey Ryan Sent: January-31-12 12:47 PM To: Dirk Eddelbuettel Cc: R-devel org Subject: Re: [Rd] seq.Date bug? 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 ;-)
From which you can get the last...
format(ISOdate(2012,1:12,1)-86400,"%d-%b-%Y")
[1] "31-Dec-2011" "31-Jan-2012" "29-Feb-2012" "31-Mar-2012" "30-Apr-2012" "31-May-2012" [7] "30-Jun-2012" "31-Jul-2012" "31-Aug-2012" "30-Sep-2012" "31-Oct-2012" "30-Nov-2012" ... though leap seconds might require a bit more tweaking... Steven McKinney Statistician Molecular Oncology and Breast Cancer Program British Columbia Cancer Research Centre
Jeff On Tue, Jan 31, 2012 at 2:37 PM, Dirk Eddelbuettel <edd at 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
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-- Jeffrey Ryan jeffrey.ryan at lemnica.com www.lemnica.com www.esotericR.com R/Finance 2012: Applied Finance with R www.RinFinance.com See you in Chicago!!!!
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