R help - Jun 2007 - Computing time differences

Dear R users, 

I have a problem computing time differences using R. 

I have a date that are given using the following format: 20080620.00, where
the 4 first digits represent the year, the next 2 ones the month and the last
2 ones the day. I would need to compute time differences between two vectors
of this given format. 

I tried around trying to change this format into any type of time serie
without any succes. 

Could some one provide me with some useful suggestion and/or tip to know
where to look?

I am using R-2.4.0 under Windows XP

Thanks for your help, 

Vincent


	[[alternative HTML version deleted]]

Try this and see the help desk article in R News 4/1:
> x <- 20080620.00
> x2 <- 20090218.00
> num2Date <- function(x) as.Date(paste(x), "%Y%m%d")
> num2Date(x2) - num2Date(x)
Time difference of 243 days
> as.numeric(num2Date(x2) - num2Date(x))
[1] 243

On 6/20/07, vincent.duval at boehringer-ingelheim.com
<vincent.duval at boehringer-ingelheim.com> wrote:
> Dear R users,
>
> I have a problem computing time differences using R.
>
> I have a date that are given using the following format: 20080620.00, where
> the 4 first digits represent the year, the next 2 ones the month and the
last
> 2 ones the day. I would need to compute time differences between two
vectors
> of this given format.
>
> I tried around trying to change this format into any type of time serie
> without any succes.
>
> Could some one provide me with some useful suggestion and/or tip to know
> where to look?
>
> I am using R-2.4.0 under Windows XP
>
> Thanks for your help,
>
> Vincent
>
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>

Here is one way:

Vector1 <- c("20080621.00","20080623.00")
Vector2 <- c("20080620.00","20080622.00")
do.call(difftime,
        c(apply(cbind(time1=Vector1,time2=Vector2),2,
              function(x) strptime(x,format="%Y%m%d.00")),
          units="hours"))

see ?strptime, ?difftime and
http://cran.r-project.org/doc/Rnews/Rnews_2004-1.pdf



--- vincent.duval at boehringer-ingelheim.com wrote:
> Dear R users, 
> 
> I have a problem computing time differences using R. 
> 
> I have a date that are given using the following format: 20080620.00, where
> the 4 first digits represent the year, the next 2 ones the month and the
> last
> 2 ones the day. I would need to compute time differences between two
> vectors
> of this given format. 
> 
> I tried around trying to change this format into any type of time serie
> without any succes. 
> 
> Could some one provide me with some useful suggestion and/or tip to know
> where to look?
> 
> I am using R-2.4.0 under Windows XP
> 
> Thanks for your help, 
> 
> Vincent
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
> 


       
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