[R] date conversion

[Joshua Wiley]

Hi,

I think you just need to add the format = argument.  Does this help?

> x <- factor("01-11-2007")
> as.character(x)
[1] "01-11-2007"
> as.Date(as.character(x), format = "%d-%m-%Y")
[1] "2007-11-01"

Cheers,

Josh

On Fri, Sep 3, 2010 at 2:11 PM, André de Boer <rnieuws at gmail.com> wrote:
>
> Hello,
>
> I have a dataframe with data such as:
> > dat$BEGINDATUM[3]
> [1] 13-09-2007
> > dat$BEGINDATUM[4]
> [1] 01-11-2007
>
> > class(dat$BEGINDATUM[3])
> [1] "factor"
>
> Now I need to make calculation with these dates.
> But I get these result:
> > as.date(as.character(dat$BEGINDATUM[3]))
> [1] <NA>
> > as.date(as.character(dat$BEGINDATUM[4]))
> [1] 11Jan2007
>
> How can i convert these factors to make calculations possible.
>
> Thanks for the answer,
> Andre
>
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>
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--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/