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

From: Milton Cezar Ribeiro <milton_ruser_at_yahoo.com.br>
Date: Tue 09 Jan 2007 - 15:51:18 GMT


Dear Peter,    

  I tryed something like    

  >head(especies.aicc)

         especie aicc

1 Attila.rufus 17.15934
2 Attila.rufus 11.41371
3 Attila.rufus 11.41371
4 Attila.rufus 19.55998
5 Attila.rufus 17.23780
6 Attila.rufus 19.22545
   
  > especies.min<-aggregate.data.frame(especies.aicc,list
             (Especie=especies.aicc$especie),max)
   

  But it works fine only for "mean" FUN and not for "min" and "max". Also also, when I use "mean" I got the following warnings:    

  > especies.min<-aggregate.data.frame(especies.aicc,list

         (Especie=especies.aicc$especie),mean)

  Warning messages:
1: argument is not numeric or logical: returning NA in: mean.default(X[[1]], ...) 2: argument is not numeric or logical: returning NA in: mean.default(X[[2]], ...)    

  In fact I need only min() and max().    

  Miltinho


Peter Dalgaard <P.Dalgaard@biostat.ku.dk> escreveu:   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 ěster 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 08:47:06 2007

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