R help - Aug 2003 - graph for selected lines in stars()

Dear listers,

The following command (derived from the example in the ?stars help page)
works :

data(mtcars)
stars(mtcars[, 1:7])

But the following gives an error:
stars(mtcars[1, 1:7])
Error in s.y[i, ] : incorrect number of dimensions

I was expecting to have the star graph for the first line (Mazda Rx4)

The following give an incorrect graph for the first two cars :
stars(mtcars[1:2, 1:7])

The following gives the correct graphs for all cars:
stars(mtcars[1:32, 1:7])

How can I have correct graphs for a selection of lines ?

I am using R 1.7.1 on linux Mandrake 9.1

Thank you for your help

Tito

> version
         _
platform i686-pc-linux-gnu
arch     i686
os       linux-gnu
system   i686, linux-gnu
status
major    1
minor    7.1
year     2003
month    06
day      16
language R

-- 
L. Tito de Morais
      UR RAP
   IRD de Dakar
      BP 1386
       Dakar
      S?n?gal

T?l.: + 221 849 33 31
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Courriel: tito at ird.sn

Tito de Morais Luis <Luis.Tito-de-Morais at ird.sn> writes:
> Dear listers,
> 
> The following command (derived from the example in the ?stars help page)
> works :
> 
> data(mtcars)
> stars(mtcars[, 1:7])
> 
> But the following gives an error:
> stars(mtcars[1, 1:7])
> Error in s.y[i, ] : incorrect number of dimensions
> 
> I was expecting to have the star graph for the first line (Mazda Rx4)
I don't think that makes sense. Star graphs are only defined for an
ensemble of rowss, at least with the default setting of 'scale=TRUE'.
 
> The following give an incorrect graph for the first two cars :
> stars(mtcars[1:2, 1:7])
Looks correct to me. 1st two models are identical on five variables,
and the remaining two are scaled to [0,1], which in this case means
that you get two zeros for the first car and two ones for the other.

> The following gives the correct graphs for all cars:
> stars(mtcars[1:32, 1:7])
> 
> How can I have correct graphs for a selection of lines ?
First define "correct". You can use scale=FALSE and do the scaling
yourself in some way that is independent of the subset chosen.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
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