R help - Nov 2007 - Dates in R

Hi,

I have dates in the following format: 4/8/2006 (MM/DD/YYYY).  I need to have R
compare date A to date B to figure out which one is more recent.  Is there a way
to do that?  Simply using the '>' or '<' signs doesn't
seem to work.  I think in this case R treats '/' as a division sign and
gives me erroneous results.

Thanks a lot for your help.
Irina


     
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Convert to Date and then compare;

> x <- as.Date("4/8/2006", "%m/%d/%Y")
> y <- as.Date("5/10/2007", "%m/%d/%Y")
> x>y
[1] FALSE
>
On Nov 28, 2007 2:44 PM, Irina Burmenko <iburmen at yahoo.com>
wrote:
> Hi,
>
> I have dates in the following format: 4/8/2006 (MM/DD/YYYY).  I need to
have R compare date A to date B to figure out which one is more recent.  Is
there a way to do that?  Simply using the '>' or '<' signs
doesn't seem to work.  I think in this case R treats '/' as a
division sign and gives me erroneous results.
>
> Thanks a lot for your help.
> Irina
>
>
>     
____________________________________________________________________________________
> Never miss a thing.  Make Yahoo your home page.
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

Irina, you must have them in character format. You need to convert to Date type.

mydates = as.Date(mydates, "%m/%d/%Y")

HTH.

Horace

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Irina Burmenko
Sent: Wednesday, November 28, 2007 11:44 AM
To: Horace Tso; r-help at r-project.org
Subject: [R] Dates in R

Hi,

I have dates in the following format: 4/8/2006 (MM/DD/YYYY).  I need to have R
compare date A to date B to figure out which one is more recent.  Is there a way
to do that?  Simply using the '>' or '<' signs doesn't
seem to work.  I think in this case R treats '/' as a division sign and
gives me erroneous results.

Thanks a lot for your help.
Irina


     
____________________________________________________________________________________
Never miss a thing.  Make Yahoo your home page.

        [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.