From plummer at iarc.fr  Tue Jul 11 19:39:22 2006
From: plummer at iarc.fr (Martyn Plummer)
Date: Tue, 11 Jul 2006 19:39:22 +0200
Subject: [Rd] [R] Date Format
In-Reply-To: <971536df0607110958x3c9596d7w19b2efb06cf25c26@mail.gmail.com>
References: <20060711162357.21469.qmail@web26309.mail.ukl.yahoo.com>
	<971536df0607110958x3c9596d7w19b2efb06cf25c26@mail.gmail.com>
Message-ID: <1152639562.2553.8.camel@seurat.iarc.fr>

I moved this to R-devel because I am wondering why the base package does
not allow you to convert from numeric to Date. Could we not have
something like this?

as.Date.numeric <- function(x, epoch="1970-01-01", ...) {
   if (!is.character(epoch) || length(epoch) != 1)
      stop("invalid epoch")
   as.Date(epoch, ...) + x
}

Martyn

On Tue, 2006-07-11 at 12:58 -0400, Gabor Grothendieck wrote:
> Try this:
> 
> library(zoo)
> as.Date(11328)
> 
> See the Help Desk article in R News 4/1 for more on dates.
> 
> 
> On 7/11/06, pierre clauss <pierreclauss at yahoo.fr> wrote:
> > Hi everybody,
> > I need your precious help for, I think, a simple request, but I do not manage to solve this.
> >
> > When I use a "table" function with dates in the rows, the rows are coerced to number after the table function.
> >
> > So I need to transform the row names into date format. But I do not manage.
> >
> > Therefore, for an example, I manage to write this :
> >
> > datetest<-"06/01/2001"
> > datetest<-as.Date(datetest,"%d/%m/%Y")
> > datetest<-as.numeric(datetest)
> >
> > to get 11328.
> >
> > But I do not obtain the inverse tranformation :
> >
> > datetest<-as.Date(datetest,"%d/%m/%Y")
> >
> > How do we get this please ?
> >
> > Thanks a lot for your solution.
> > Pierre.
> >
> >

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[Rd] [R] Date Format
Martyn Plummer