[R] getting ISO week

[Hans W. Borchers]

Gabor Grothendieck <ggrothendieck <at> gmail.com> writes:

> 
> format(d, "%U") and format(d, "%W") give week numbers using
> different conventions.  See ?strptime

Gabor,

the results of format(aDate, "W") appear to be incorrect anyway, see:

    format(as.Date("2008-01-01"), "%W")     #-> "00"

There is never a week 0, this should be week 1.

    format(Sys.Date(), "%W")                #-> "49"

but my business calendar says today's (Dec. 11, 2008) week is week 50
which is what Brian Ripleys proposed 'strftime(x, "%V")' returns.

There could be a format "%E" (not used up to now) for returning a
correct week number according to the European standard.

Yours,  Hans Werner

> On Thu, Dec 11, 2008 at 7:43 AM, Gustaf Rydevik
> <gustaf.rydevik <at> gmail.com> wrote:
> > Hi all,
> >
> > Is there a simple function already implemented for getting the ISO
> > weeks of a Date object?
> > I couldn't find one, and so wrote my own function to do it, but would
> > appreciate a pointer to the "default" way. If a function is not yet
> > implemented, could the code below be of interest to submit to CRAN?
> >
> > Best Regards,
> >
> > Gustaf
> >
> > --------------------
> 
> ... [rest deleted]
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