Re: [R] min() return factor class values

From: Peter Dalgaard <P.Dalgaard_at_biostat.ku.dk>
Date: Tue 09 Jan 2007 - 14:47:57 GMT

Milton Cezar Ribeiro wrote:
> Hi R-friends
>
> I don´t know why the "min()" function below return the min value as factor. When i force the aicc.min using a as.numeric() function, it return a factor index (1,2,..) and not min value as I want. By the way, I included a sessionInfo() at the end of this e-mail.
>
min() is not doing anything out of the ordinary, but cbind'ing it with the character vector sp coerces it to character and rbind'ing to a data frame turns character vectors into factors...

The whole thing looks like it could be a straightforward application of aggregate().
>
> In fact I had the same problem (values as factor) on other part of my script and I noticed that it occour when I use "cbind()". It is real?
>
> Any idea?
>
> Kind regards,
>
> Miltinho
>
> > especies.aicc.min<-data.frame()
>

>> for (sp in levels(especies.aicc$especie)) 
>>     

> + {
> + sele<-subset(especies.aicc,especie==sp)
> + especies.aicc.min<-rbind(especies.aicc.min,cbind(sp,aicc.min=min(sele$aicc)))
> + }
>
>> especies.aicc.min
>>     

> sp aicc.min
> 1 Attila.rufus 6.7387056413613
> 2 Automolus.leucophthalmus 125.791300522824
>
>> class(especies.aicc.min$aicc.min)
>>     

> [1] "factor"
>
> -----------
> > sessionInfo()
> R version 2.4.0 (2006-10-03)
> i386-pc-mingw32
> locale:
> LC_COLLATE=English_Jamaica.1252;LC_CTYPE=English_Jamaica.1252;LC_MONETARY=English_Jamaica.1252;LC_NUMERIC=C;LC_TIME=English_Jamaica.1252
> attached base packages:
> [1] "methods" "stats" "graphics" "grDevices" "utils" "datasets" "base"
>
>
>
-- 
   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@biostat.ku.dk)                  FAX: (+45) 35327907

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Received on Wed Jan 10 14:53:44 2007

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