Peter Dalgaard wrote:
> Rolf Turner wrote:
>
>> P.S. ***Are*** there any risks/dangers in following Christos
>> Hatzis' suggestion of simply doing
>>
>> levels(fff) <- c("U","A","S") ???
>>
> Not if the levels are right to begin with.
>
> Problems only arise if fff somehow becomes a two-level factor, e.g. if
>
Doh. Sorry. Mixing up the examples there: "...arise if fff somehow
loses levels..." the example below of course has two levels reduced to a
one.
> you do
> fff <- fff[2:3, drop=TRUE].
> Then you can get this effect:
>
> > fff
> [1] Unit Scholarship Scholarship Unit
> Levels: Scholarship Unit
> > fff[2:3, drop=TRUE]
> [1] Scholarship Scholarship
> Levels: Scholarship
> > fff[-(2:3), drop=TRUE]
> [1] Unit Unit
> Levels: Unit
> > ggg <- fff[2:3, drop=TRUE]
> > levels(ggg) <- c("a","b")
> > ggg
> [1] a a
> Levels: a b
> > ggg <- fff[-(2:3), drop=TRUE]
> > levels(ggg) <- c("a","b")
> > ggg
> [1] a a
> Levels: a b
>
>
>
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
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