[R] Problems with aggregate

[Henrique Dallazuanna]

You can use match.fun

x
  V1  V2
1  2 3.2
2 15 1.2
3  2 8.4
4  8 9.2
5  7 0.4

min <- aggregate(x, list(x[,1]), min)
min <- aggregate(x, list(x[,1]), match.fun(min))


On 21/02/2008, Mcmahon, Kevin <kwyatt.mcmahon at ttuhsc.edu> wrote:
> Hello list,
>
>
>
>  I'm new to this list, so please forgive my ignorance.  I have searched
>  R-help for some hints into what might be my problem, but I truly have no
>  idea where to go from here.
>
>
>
>  I have an object of approximately 15,000 rows and 2 columns.  There are
>  many duplicates in the first column, all with different corresponding
>  values in the second column.  For example (2 is duplicated):
>
>  2    3.2
>
>  15  1.2
>
>  2    8.4
>
>  8    9.2
>
>  7    0.4
>
>
>
>  I used the following code to aggregate these based on the first column
>  and get the min and max:
>
>  min<-aggregate(as.numeric(humanneph[,2]),
>  list(as.numeric(humanneph[,1])), min)
>
>  max<-aggregate(as.numeric(humanneph[,2]),
>  list(as.numeric(humanneph[,1])), max)
>
>
>
>  Both worked beautifully!
>
>
>
>  THEN, I accidentally overwrote the object min.  Since I hadn't touched
>  the object humanneph, I copied the above code from my saved history and
>  re-ran it.  I get the following error:
>
>  Error in FUN(X[[1L]], ...) : argument "INDEX" is missing, with no
>  default
>
>
>
>  So, I went back and again, copying directly from my saved history,
>  re-made my object humanneph, and re-ran the above code again.  Still the
>  same problem!!!
>
>
>
>  So, it seems that after running this code once, suddenly aggregate does
>  not work!!!
>
>
>
>  Can anyone help me?
>
>
>
>  My sessionInfo()
>
>  R version 2.5.1 (2007-06-27)
>
>  i386-pc-mingw32
>
>
>
>  attached base packages:
>
>  [1] "stats"     "graphics"  "grDevices" "utils"     "datasets"
>  "methods"
>
>  [7] "base"
>
>
>
>  Thanks!
>
>  Wyatt
>
>
>
>  K. Wyatt McMahon, Ph.D.
>
>  Postdoctoral Research Associate
>
>  Department of Internal Medicine
>
>  Texas Tech University Health Sciences Center
>
>  Lubbock, TX
>
>  79430
>
>  (806)743-4072
>
>
>
>
>         [[alternative HTML version deleted]]
>
>  ______________________________________________
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>  PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>  and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O