# [R] factor as seq() in for loop

Tord Snall Tord.Snall at helsinki.fi
Wed Sep 21 18:22:44 CEST 2005

```Dear Spencer,

Yes, as did the earlier replies. Thanks!

Tord

>
>  > aFactor <- factor(rep(letters[1:3], 1:3))
>  > aFactor
> [1] a b b c c c
> Levels: a b c
>  > for(af in levels(aFactor)){
> +   print(sum(aFactor==af))
> + }
> [1] 1
> [1] 2
> [1] 3
>
> 	  spencer graves
>
> Tord Snall wrote:
>
> > Dear all,
> > I would like to use the values in vegaggr.BLMCMR02\$colony
> >
> > str(vegaggr.BLMCMR02)
> > `data.frame':   1678 obs. of  3 variables:
> > \$ vegtype       : Factor w/ 27 levels "2010","2020",..: 3 4 5 19 4 5 19
> 5
> > \$ colony        : Factor w/ 406 levels "0","1","10","100",..: 1 1 1 1 2
> 2 2
> > \$ Totvegproparea: num  0.00055 0.03956 0.95705 0.00284 0.05215 ...
> >
> > as the seq in a for loop (for(var in seq)), and therefore first picked
> them
> > out as
> > cols = aggregate(list(A = vegaggr.BLMCMR02\$Totvegproparea),
> >                 list(colony = vegaggr.BLMCMR02\$colony), sum)[,1]
> >
> >>str(cols)
> >
> >  Factor w/ 406 levels "0","1","10","100",..: 1 2 3 4 5 6 7 8 9 10 ...
> >
> > I next planned to transform cols using as.integer(cols). However, this
>
> > transformation gives a vector corresponding to
> seq(from=1,to=length(cols)).
> >
> > Could someone please give advice on how to make use of a factor as the
> seq
> > in a for loop (which is strictly not allowed' according to ?Control).
> >
> > Thanks!
> >
> > Tord
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> http://www.R-project.org/posting-guide.html
>
> --
> Spencer Graves, PhD
> Senior Development Engineer
> PDF Solutions, Inc.
> 333 West San Carlos Street Suite 700
> San Jose, CA 95110, USA
>
> spencer.graves at pdf.com
> www.pdf.com <http://www.pdf.com>
> Tel:  408-938-4420
> Fax: 408-280-7915
>

```