[R] NA, where no NA should (could!) be!

[Peter Dalgaard]

Oliver Bandel wrote:
> Hello,
> 
> 
> ok, I found the problem!
> 
> 
> 
> I now have:
> 
>     res_size_by_host <- tapply( selected$size, factor(selected$host), sum)
> 
> 
> instead of
> 
>   
>   res_size_by_host <- tapply( selected$size, selected$host, sum)
> 
> 
> and now it works.
> 
> IMHO this is strange, because selected$host is already a factor!
> 
> 
> I don't know, why this must be done...
> ...someone of the R-experts might know it...
> ...and may explain it...?!

I already told you: You have empty levels in selected$host. Look at the 
example I showed you.


-- 
    O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
   c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
  (*) \(*) -- University of Copenhagen   Denmark      Ph:  (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)              FAX: (+45) 35327907