[R] help with writing function

[Petr Pikal]

Hi

or use outer

x<-1:10
x<-sample(x)
mat<-outer(x,x,"-") # result with zeroes
matrix(mat[!mat==0],9,9) # get rid of them

will give you a matrix with columns with intended result.

HTH
Petr




On 13 Dec 2005 at 11:53, Robert Burrows wrote:

Date sent:      	Tue, 13 Dec 2005 11:53:00 -0500 (EST)
From:           	Robert Burrows <rbb at nebiometrics.com>
To:             	Oarabile Molaodi <oarabile at stams.strath.ac.uk>
Copies to:      	r-help at stat.math.ethz.ch
Subject:        	Re: [R] help with writing function

> On Tue, 13 Dec 2005, Oarabile Molaodi wrote:
> 
> > I'm trying to write a function that takes a vector of length n  and
> > then takes the first value of the vector i.e j=1 and forms a new
> > vector of length n (i.e replicate the first value n times). This
> > function will then calculate the absoulte difference of the original
> > vector and the new vector and store the results omitting the
> > difference between the value and itself. This function should be
> > able to repeat the procedure for each of the j's i.e j=2 to n. The
> > results should all be stored together. Below is  what I've tried so
> > far but it seems to work only for j=1 .
> >
> > Your help will be highly appreciated.
> > IED<-function(risk){
> > n<-length(risk)
> > i<-c(1:n)
> > Diff<-numeric()
> > for(j in 1:n){
> > relrisk<-risk
> > relrisk[i]<-relrisk[j]
> > Difference<-abs(risk-relrisk)
> > Difference<-Difference[-c(1:j)]
> > Difference<-append(Diff,Difference)
> > return(Difference)
> > }
> > }
> 
> How about
> 
> "IED" <-
> function(risk){
>   n<-length(risk)
> Diff<-numeric(n)
> for(j in 1:n){
> relrisk<-rep(risk[j],n)
> Diff[j]<-sum(abs(risk-relrisk)[-j])
> }
> Diff
> }
> 
> -- 
> Robert Burrows, PhD
> New England Biometrics
> rbb at nebiometrics.com
> 
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Petr Pikal
petr.pikal at precheza.cz