Re: [R] initialize a factor vector

From: Johannes Huesing <johannes_at_huesing.name>
Date: Sat, 19 Jul 2008 15:20:28 +0200

I have found that factor vectors are shy beasts.

Consider:

> empty <- factor(levels=c("eins", "zwei"))
> value <- factor("eins", levels=c("eins", "zwei"))
> c(empty, value)

[1] 1
> empty[1] <- value
> empty

[1] eins
Levels: eins zwei
>

I could not exactly predict this behaviour, but ?c says:

    The output type is determined from the highest type of the

     components in the hierarchy NULL < raw < logical < integer < real
     < complex < character < list < expression. 

As factor is a class (of the whole vector) and not a type (of a single element), c does not seem to preserve the object information, i.e. there does not seem to be a c.factor, correct?

-- 
Johannes Hüsing               There is something fascinating about science. 
                              One gets such wholesale returns of conjecture 
mailto:johannes_at_huesing.name  from such a trifling investment of fact.                
http://derwisch.wikidot.com         (Mark Twain, "Life on the Mississippi")

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Received on Sat 19 Jul 2008 - 13:23:33 GMT

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