[R] colour coding and different point types in a plot

[Peter Dalgaard BSA]

"Grum, Mikkel" <M.GRUM at CGIAR.ORG> writes:

> I'm trying to plot four different sorghum types on a plot using a different
> colour/symbol combination for each sorghum type (TYPBOTA in the script
> below).  What am I doing wrong?:
> 
> plot(xx$LATITUDE,xx$SFD1,
>    points(xx$SFD1,xx$LATITUDE,
>    col=1:4[codes(xx$TYPBOTA)],pch=c(4,3,1,2)[codes(xx$TYPBOTA)])
> grid()
> 
> I get the following error message
> Error in 1:4[codes(xx$TYPBOTA)] : NA/NaN argument
> In addition: Warning message: 
> Numerical expression has 162 elements: only the first used in:
> 1:4[codes(xx78$TYPBOTA)] 

I think you need (1:4)[...] (and maybe also reconsider the use of
codes(). It has certain surprises, and indexing with a factor is the
same as using foo[as.integer(f)]) 

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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