[R] Merging factor levels.

[John Fox]

Dear Goran,

The recode function in the car package does a variety of recodes, including 
of factors. In your case, you would specify:

         okk <- recode(okk, " 'NEAR_TOWN' = 'Other' ")

I hope that you find this useful.

John

At 05:05 PM 11/12/2001 +0000, Prof Brian D Ripley wrote:
>On Mon, 12 Nov 2001, [iso-8859-1] Göran Broström wrote:
>
> > This must be a FAQ, but I can't find the answer:
> > I have a factor 'okk':
> >
> > > table(okk)
> > okk
> >      Other   STORKAGE SKELLEFTEA    FALMARK       BOLE  NEAR_TOWN
> >      14064        560        346        526        332         34
> >
> > Now I want to put the cases in 'NEAR_TOWN' into the 'Other' category',
> > so I try:
> >
> > > okk <- ifelse(okk == "NEAR_TOWN", "Other", okk)
> > > table(okk)
> > okk
> >     1     2     3     4     5 Other
> > 14064   560   346   526   332    34
> > > is.factor(okk)
> > [1] FALSE
> >
> > This is not what I intended. I can do what I want the hard way (i.e., by
> > converting  okk  to character an then back again) but there
> > must be something simpler?
>
>Something like
>
>levels(okk) <- c(levels(okk)[1:5], "Other")
>
>If you set two levels to be the same label, they get merged.
>
>--
>Brian D. Ripley,                  ripley at stats.ox.ac.uk
>Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
>University of Oxford,             Tel:  +44 1865 272861 (self)
>1 South Parks Road,                     +44 1865 272860 (secr)
>Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>
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-----------------------------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario, Canada L8S 4M4
email: jfox at mcmaster.ca
phone: 905-525-9140x23604
web: www.socsci.mcmaster.ca/jfox
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