[R] factor based on pattern match ?

[Oleg Bartunov]

On Thu, 25 Mar 2004, Liaw, Andy wrote:

> Is the following sort of what you want?

thanks for example, but I need something more :)
In real situation, I'd like to use perl like patterns (like in grep),
or just implicitly specify levels, for example: level F is ("f.*", "mmm")


>
> > y = factor(c("ff","f","m","mm","fm","mf","ffm","mmf","mmm","fff"))
> > levels(y) <- substring(levels(y), 1, 1)
> > y
>  [1] f f m m f m f m m f
> Levels: f m
>
> Andy
>
> > From: Oleg Bartunov
> >
> > Hello,
> >
> > is't possible to specify pattern in levels ?
> >
> > > y=c("ff","f","m","mm","fm","mf","ffm","mmf","mmm","fff");
> > > factor(y)
> >  [1] ff  f   m   mm  fm  mf  ffm mmf mmm fff
> > Levels: f ff fff ffm fm m mf mm mmf mmm
> >
> > I want to specify levels using regexp ("f.*","m.*") or use some
> > another method. So, I could have 2 levels, say, F and M, where
> > F means everything  beginning from 'f' and M - from 'm'.
> >
> > Something like cut() for numerical data.
> >
> > 	Regards,
> > 		Oleg
> > _____________________________________________________________
> > Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
> > Sternberg Astronomical Institute, Moscow University (Russia)
> > Internet: oleg at sai.msu.su, http://www.sai.msu.su/~megera/
> > phone: +007(095)939-16-83, +007(095)939-23-83
> >
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> >
>
>
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	Regards,
		Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg at sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83