[R] easier way to do this without a loop? (successive euclidean distances between points)

[Henrique Dallazuanna]

Or just:

diag(rdist(z, z)[,-1])

On Mon, Oct 6, 2008 at 1:58 PM, Henrique Dallazuanna <wwwhsd at gmail.com> wrote:
> 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
>>
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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.
>>
>
>
>
> --
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O