Try following this example:
mydf <- data.frame(t1=c('201112312230', '201112312330'))
tmp1 <- as.POSIXct(mydf$t1, format='%Y%m%d%H%M')
tmp2 <- tmp1 - 30*60
mydf$t2 <- format(tmp2, '%Y%m%d%H%M')
It can be made into a single line, but I used intermediate variables tmp1
and tmp2 so that it would be easier to follow.
Base R is more than adequate for this task.
Please get rid of the asterisks in your next email. The just get in the
way. Learn how to send plain text email, not HTML email. Please.
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
On 8/31/16, 9:07 AM, "R-help on behalf of Bhaskar Mitra"
<r-help-boun...@r-project.org on behalf of bhaskar.kolk...@gmail.com>
wrote:
>Hello Everyone,
>
>I am trying a shift the time series in a dataframe (df) by 30 minutes . My
>current format looks something like this :
>
>
>
>*df$$Time 1*
>
>
>*201112312230*
>
>*201112312300*
>
>*201112312330*
>
>
>
>*I am trying to add an additional column of time (df$Time 2) next to Time
>1 by lagging it by 30minutes. Something like this :*
>
>
>*df$Time1 **df$$Time2*
>
>
>*201112312230 **201112312200*
>
>*201112312300 **201112312230*
>
>*201112312330 **201112312300*
>
>*201112312330 *
>
>
>
>
>
>*Based on some of the suggestions available, I have tried this option *
>
>
>
>*require(zoo)*
>
>*df1$Time2 <- lag(df1$Time1, -1, na.pad = TRUE)*
>
>*View(df1)*
>
>
>
>*This does not however give me the desired result. I would appreciate any
>suggestions/advice in this regard.*
>
>
>*Thanks,*
>
>*Bhaskar*
>
> [[alternative HTML version deleted]]
>
>______________________________________________
>R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
