R help - Nov 2012 - help with if statement

Hi all,

I had a dataset A like:

TIME  DV
0  0
1   10
5    20
24  30
36   80
48  60
72 15

I would like to add 24 to those values higher than 24 in the TIME column. 

I did the following:

If (A$TIME>=24) {
A$TIME <- A$TIME+24}

It did not work.  How should I do it?

Thanks,



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Use ifelse().

ifelse(A$TIME >= 24, A$TIME + 24, A$TIME)

Please in the future use dput() to provide your data, and explain what
"did not work" means.

Sarah

On Wed, Nov 21, 2012 at 12:05 PM, york8866 <yu_york at hotmail.com>
wrote:
> Hi all,
>
> I had a dataset A like:
>
> TIME  DV
> 0  0
> 1   10
> 5    20
> 24  30
> 36   80
> 48  60
> 72 15
>
> I would like to add 24 to those values higher than 24 in the TIME column.
>
> I did the following:
>
> If (A$TIME>=24) {
> A$TIME <- A$TIME+24}
>
> It did not work.  How should I do it?
>
> Thanks,
>
>
>
--
Sarah Goslee
http://www.functionaldiversity.org

Does 

A$TIME <- ifelse( A$TIME >= 24, A$TIME + 24, A$TIME )

what you want?

Rgds,
Rainer


On Wednesday 21 November 2012 09:05:39 york8866 wrote:
> Hi all,
> 
> I had a dataset A like:
> 
> TIME  DV
> 0  0
> 1   10
> 5    20
> 24  30
> 36   80
> 48  60
> 72 15
> 
> I would like to add 24 to those values higher than 24 in the TIME column. 
> 
> I did the following:
> 
> If (A$TIME>=24) {
> A$TIME <- A$TIME+24}
> 
> It did not work.  How should I do it?
> 
> Thanks,
> 
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/help-with-if-statement-tp4650315.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> 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.

On Nov 21, 2012, at 9:05 AM, york8866 wrote:
> Hi all,
>
> I had a dataset A like:
>
> TIME  DV
> 0  0
> 1   10
> 5    20
> 24  30
> 36   80
> 48  60
> 72 15
>
> I would like to add 24 to those values higher than 24 in the TIME  
> column.
>
> I did the following:
>
> If (A$TIME>=24) {
> A$TIME <- A$TIME+24}
>
> It did not work.  How should I do it?
You should study the help pages for if and ifelse:

?"if"
?ifelse

-- 

David Winsemius, MD
Alameda, CA, USA

DT<-data.frame(time=c(0,1,5,24,36,48,72),DV=seq(0,60,10))
  time DV
1    0  0
2    1 10
3    5 20
4   48 30
5   84 40
6   96 50
7  120 60
You want to add 24 to values that are >=24 in 'time'

DT[DT$time>=24,'time']<-DT[DT$time>=24,'time']+24
  time DV
1    0  0
2    1 10
3    5 20
4   48 30
5   60 40
6   72 50
7   96 60

Is this what you were looking for?
A.




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