[R] factor as seq() in for loop

[Tord Snall]

Dear Spencer,

> 	  Does the follow help?

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
> > 
> > ______________________________________________
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> 
> -- 
> Spencer Graves, PhD
> Senior Development Engineer
> PDF Solutions, Inc.
> 333 West San Carlos Street Suite 700
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> 
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