R help - Mar 2010 - simple loop iteration

Hi R mailing list,

probably a very basic problem here, I try to do the following:
> Q<-c(1,2,3)
> P<-c(4,5,6)
> A<- data.frame(Q,P)
> A
  Q P
1 1 4
2 2 5
3 3 6

this is my simplified data.frame (matrix) now I try to create following
loop for subtraction of element within the data.frame:
> for(i in length(A[,"P"]-1){
  delta[i]<- A[i,"P"]-A[i+1,"P"]
}

All I get is a vector of  the correct length but with no readings.

Thanks for any help on this.



-- 
Niklaus Hürlimann

Université de Lausanne  
Institut de Minéralogie et Géochimie 
L'Anthropole 
CH-1015 Lausanne 
Suisse

E-mail: Niklaus.Hurlimann@unil.ch
Tel:+41(0)21 692 4452 

	[[alternative HTML version deleted]]

Try this:

Reduce("-", as.data.frame(embed(A$P, 2)))

On Tue, Mar 30, 2010 at 10:15 AM, Niklaus Hurlimann
<niklaus.hurlimann at unil.ch> wrote:
> Hi R mailing list,
>
> probably a very basic problem here, I try to do the following:
>
>> Q<-c(1,2,3)
>> P<-c(4,5,6)
>> A<- data.frame(Q,P)
>> A
> ?Q P
> 1 1 4
> 2 2 5
> 3 3 6
>
> this is my simplified data.frame (matrix) now I try to create following
> loop for subtraction of element within the data.frame:
>
>> for(i in length(A[,"P"]-1){
> ?delta[i]<- A[i,"P"]-A[i+1,"P"]
> }
>
> All I get is a vector of ?the correct length but with no readings.
>
> Thanks for any help on this.
>
>
>
> --
> Niklaus H?rlimann
>
> Universit? de Lausanne
> Institut de Min?ralogie et G?ochimie
> L'Anthropole
> CH-1015 Lausanne
> Suisse
>
> E-mail: Niklaus.Hurlimann at unil.ch
> Tel:+41(0)21 692 4452
>
> ? ? ? ?[[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.
>
>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O

Perhaps you're just looking for the diff() function?
See ?diff.

  -Peter Ehlers

On 2010-03-30 7:15, Niklaus Hurlimann wrote:
> Hi R mailing list,
>
> probably a very basic problem here, I try to do the following:
>
>> Q<-c(1,2,3)
>> P<-c(4,5,6)
>> A<- data.frame(Q,P)
>> A
>    Q P
> 1 1 4
> 2 2 5
> 3 3 6
>
> this is my simplified data.frame (matrix) now I try to create following
> loop for subtraction of element within the data.frame:
>
>> for(i in length(A[,"P"]-1){
>    delta[i]<- A[i,"P"]-A[i+1,"P"]
> }
>
> All I get is a vector of  the correct length but with no readings.
>
> Thanks for any help on this.
>
>
>
>
>
>
> ______________________________________________
> 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.
-- 
Peter Ehlers
University of Calgary