[R] Bug in seq.date?

[hadley wickham]

On 6/4/07, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> Note that chron does give the last day of the month:
>
> > library(chron)
> > seq(chron("1/31/2000"), chron("1/31/2001"), "month")
>  [1] 01/31/00 02/29/00 03/31/00 04/30/00 05/31/00 06/30/00 07/31/00 08/31/00
>  [9] 09/30/00 10/31/00 11/30/00 12/31/00 01/31/01

Thanks, that's very useful - I'll switch to using chron instead.

Hadley

> The zoo package has a "yearmon" class whose as.Date.yearmon can
> convert a "Date" to the end of the month:
> library(zoo)
> > library(zoo)
> > as.Date(as.yearmon(seq(as.Date("2000-1-31"), as.Date("2001-1-31"), "month")), 1)
>  [1] "2000-01-31" "2000-02-29" "2000-03-31" "2000-04-30" "2000-05-31"
>  [6] "2000-06-30" "2000-07-31" "2000-08-31" "2000-09-30" "2000-10-31"
> [11] "2000-11-30" "2000-12-31" "2001-01-31"
>
> And we do it ourself like this:
>
> > as.Date(format(seq(as.Date("2000-1-1"), as.Date("2001-1-1"), "month") + 32, "%Y-%m-01"))-1
>  [1] "2000-01-31" "2000-02-29" "2000-03-31" "2000-04-30" "2000-05-31"
>  [6] "2000-06-30" "2000-07-31" "2000-08-31" "2000-09-30" "2000-10-31"
> [11] "2000-11-30" "2000-12-31" "2001-01-31"
>
>
>
>
> On 6/4/07, hadley wickham <h.wickham at gmail.com> wrote:
> > > seq(as.Date("2000-1-1"), as.Date("2001-1-1"), "months")
> >  [1] "2000-01-01" "2000-02-01" "2000-03-01" "2000-04-01" "2000-05-01"
> >  [6] "2000-06-01" "2000-07-01" "2000-08-01" "2000-09-01" "2000-10-01"
> > [11] "2000-11-01" "2000-12-01" "2001-01-01"
> >
> >
> > > seq(as.Date("2000-1-31"), as.Date("2001-1-31"), "months")
> >  [1] "2000-01-31" "2000-03-02" "2000-03-31" "2000-05-01" "2000-05-31"
> >  [6] "2000-07-01" "2000-07-31" "2000-08-31" "2000-10-01" "2000-10-31"
> > [11] "2000-12-01" "2000-12-31" "2001-01-31"
> >
> > Is this a bug?
> >
> > Hadley
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch 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.
> >
>