[EMAIL PROTECTED] wrote:
>
> Full_Name: Daniel Frey
> Version: 1.7.1
> OS: Windows 2000
> Submission from: (NULL) (80.254.164.242)
>
> Generating a data frame out of a xtabs result acts unusual. Take the following
> sample to reproduce it:
>
> > a.a <- c("a","a","a","b","b")
>
> > a.b <- c("c","c","d","e","f")
>
> > a.df <- data.frame(list("A"=a.a,"B"=a.b))
>
> > a.x <- xtabs(~A+B,a.df)
>
> > a.x
> B
> A c d e f
> a 2 1 0 0
> b 0 0 1 1
>
> > data.frame(a.x)
> A B Freq
> 1 a c 2
> 2 b c 0
> 3 a d 1
> 4 b d 0
> 5 a e 0
> 6 b e 1
> 7 a f 0
> 8 b f 1
>
> I would expect something like a.x itself. Instead I have to give the exact
> bounds, otherwise it doesn't convert properly:
>
> > data.frame(a.x[1:2,1:4])
> c d e f
> a 2 1 0 0
> b 0 0 1 1
>
> I consider this a bug, as consistency of the handling breaks here.
>
> Daniel Frey
a) data.frame() calls as.data.frame()
b) as.data.frame() uses its method as.data.frame.table(), because
class(a.x)
[1] "xtabs" "table"
c) ?as.data.frame.table tells us:
`as.data.frame.table' is a method for the generic function
`as.data.frame' to convert the array-based representation of a
contingency table to a data frame containing the classifying
factors and the corresponding counts (the latter as component
`Freq'). This is the inverse of `xtabs'.
So, what is the bug?
I guess you expect something like
data.frame(unclass(a.x))
Uwe Ligges
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