Re: [R] colClasses = "Date" in read.delim, how to pass date-format?

From: Christoph Lehmann <christoph.lehmann_at_gmx.ch>
Date: Tue 19 Apr 2005 - 04:04:30 EST

so what do you recommend: I just need to be able to sort a data.frame according to the date entry, and e.g. compute differences between subsequent dates. Shall I stay with dates (thanks for the hint about confusion of Date and dates) or is there a better way for this kind of task?

thanks a lot
Cheers
Christoph
> You are confusing class "Date" (part of R) with class "dates" (part of
> package chron). There is no as() method for class "dates", so you can't
> do this. You can read the column as character (not factor) and convert
> later, but it sounds like the `huge amount of memory (and time)' is in
> fact taken by package chron.
>
> On Mon, 18 Apr 2005, Christoph Lehmann wrote:
>
> > I have a huge data-set with one column being of type date.
> > Of course I can import the data using this column as "factor" and then
> > convert it later to dates, using:
> >
> > sws.bezuege$FaktDat <- dates(as.character(sws.bezuege$FaktDat),
> > format = c(dates = "d.m.y"))
> >
> >
> > But the conversion requires a huge amount of memory (and time),
> therefore I
> > would like to use colClasses = c("Date"). My question is:
> > since I have format = c(dates = "d.m.y"), how can I pass this option to
> > read.delim(..., colClasses = c("Date")) ?
>
> --
> Brian D. Ripley, ripley@stats.ox.ac.uk
> Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
> University of Oxford, Tel: +44 1865 272861 (self)
> 1 South Parks Road, +44 1865 272866 (PA)
> Oxford OX1 3TG, UK Fax: +44 1865 272595
>

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Received on Tue Apr 19 04:09:45 2005

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