[R] How do I use as.Date when day values are missing?

[Gabor Grothendieck]

On Mon, Feb 25, 2008 at 6:03 AM, Peter Dalgaard
<P.Dalgaard at biostat.ku.dk> wrote:
> Gabor Grothendieck wrote:
> > In looking at this again here is a slight simplification.  Its now
> > only one line:
> >
> >
> >> library(chron)
> >> x <- c("01/00/05", "01/22/06")
> >> as.chron(sub("/00/", "/15/", x)) + (regexpr("/00/", x) > 0) / 2
> >>
> > [1] (01/15/05 12:00:00) (01/22/06 00:00:00)
> >
> You don't really need chron here, do you?
>
> as.Date(sub("/00/", "/15/", x), format="%m/%d/%y")
>
> (The format spec seems to have been left out below. Also, beware the
> system-dependence of %y.)

Yes, you need chron since entire point was to encode the missings as
noon so one can reverse the procedure and Date does not support times.
Also the format was omitted because its not required.  m/d/y is the default
for chron.