# [R] help me understand how things work.

Mario Valle mvalle at cscs.ch
Thu Sep 16 14:42:46 CEST 2010

```  print(k) and you see a lower triangular distance matrix.
k[1] selects distances between 1 and 2
k[2] selects distances between 1 and 3 and so on.
you have a distance matrix, not a single distance value, so you have to
select which distance you need.
Ciao!
mario

On 16-Sep-10 14:38, Alaios wrote:
> I fixed by adding this:
>
> k <- sqrt(dist(temp))
> k returns sort of a list. So I need to select the first item which is
> the result.
> a <- k[1]
>
> Can someone explain me why k[1] is needed for that?
>
> Best Regards
> Alex
>
> ------------------------------------------------------------------------
> *From:* Mario Valle <mvalle at cscs.ch>
> *To:* Alaios <alaios at yahoo.com>
> *Sent:* Thu, September 16, 2010 1:28:31 PM
> *Subject:* Re: [R] help me understand how things work.
>
>   ?dist
> BTW, to me this does not happens.
> x <- matrix(rnorm(100), nrow=5)
> d <- dist(x)
> 1/sqrt(d)
> 1/sqrt(dist(x))
>
> Hope it helps
>                                     mario
> On 16-Sep-10 12:02, Alaios wrote:
> > Hello I have some strange output from R and I try to understand how
> R works.
> >
> >
> > temp<- rbind (c(10,1),c(99,98))
> >> temp
> >      [,1] [,2]
> > [1,]  10    1
> > [2,]  99  98
> >
> >
> >> dist(temp)
> >          1
> > 2  131.6435
> >
> >
> >> sqrt(dist(temp))
> >          1
> > 2  11.47360
> >
> > so far so good.
> >
> > until the nex line: when I try to do what i did before but adding
> the 1/(what I
> > did before). I was expecting a number as a result of the division but
> > unfortunately I took the following:
> >
> >  1/sqrt(dist(temp))
> > [1] 0.08715662
> > attr(,"Size")
> > [1] 2
> > attr(,"Diag")
> > [1] FALSE
> > attr(,"Upper")
> > [1] FALSE
> > attr(,"method")
> > [1] "euclidean"
> > attr(,"call")
> > dist(x = temp)
> > attr(,"class")
> > [1] "dist"
> >
> >
> >
> > I would like to thank you in advance for your help
> > Best REgards
> > Alex
> >
> >
> >
> >
> >     [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at r-project.org <mailto:R-help at r-project.org> mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> --
> Ing. Mario Valle
> Data Analysis and Visualization Group            |
> http://www.cscs.ch/~mvalle <http://www.cscs.ch/%7Emvalle>
> Swiss National Supercomputing Centre (CSCS)      | Tel:  +41 (91)
> 610.82.60
> v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax:  +41 (91)
> 610.82.82
>
>

--
Ing. Mario Valle
Data Analysis and Visualization Group            | http://www.cscs.ch/~mvalle
Swiss National Supercomputing Centre (CSCS)      | Tel:  +41 (91) 610.82.60
v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax:  +41 (91) 610.82.82

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