R help - Oct 2008 - easier way to do this without a loop? (successive euclidean distances between points)

a <- c(1:10)
b <- c(.5, .6, .9, 10, .4, 3, 4, 9, 0, 11)
d <- c(21:30)

z <- data.frame(a,b,d)
library(fields)
results <- c()
for(i in 1:(length(rownames(z))-1)){
  results[i] <- rdist(z[i,], z[(i+1),])
 }

results.1 <- data.frame(results)	
  f <- rownames(z)
  r <- f[-1]
  rownames(results.1) <- r
  colnames(results.1) <- f[1]

this does what I want it to do - is there an easier/generic way of
doing this.  I will be using this to calculate euclidean distances
between successive time steps on ordination scores.
thanks

-- 
Stephen Sefick
Research Scientist
Southeastern Natural Sciences Academy

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.  We are mammals, and have not exhausted the
annoying little problems of being mammals.

								-K. Mullis

Try this:

diag(rdist(rbind(z, 0), rbind(0, z))[,-(1:2)])

On Mon, Oct 6, 2008 at 1:49 PM, stephen sefick <ssefick at gmail.com>
wrote:
> a <- c(1:10)
> b <- c(.5, .6, .9, 10, .4, 3, 4, 9, 0, 11)
> d <- c(21:30)
>
> z <- data.frame(a,b,d)
> library(fields)
> results <- c()
> for(i in 1:(length(rownames(z))-1)){
>  results[i] <- rdist(z[i,], z[(i+1),])
>  }
>
> results.1 <- data.frame(results)
>  f <- rownames(z)
>  r <- f[-1]
>  rownames(results.1) <- r
>  colnames(results.1) <- f[1]
>
> this does what I want it to do - is there an easier/generic way of
> doing this.  I will be using this to calculate euclidean distances
> between successive time steps on ordination scores.
> thanks
>
> --
> Stephen Sefick
> Research Scientist
> Southeastern Natural Sciences Academy
>
> Let's not spend our time and resources thinking about things that are
> so little or so large that all they really do for us is puff us up and
> make us feel like gods.  We are mammals, and have not exhausted the
> annoying little problems of being mammals.
>
>                                                                -K. Mullis
>
> ______________________________________________
> 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