[R] Odp: Showing NAs when using table()

[Petr PIKAL]

Hi

problem is with your extra empty levels in your d factor. Without it

> d1<-factor(d, exclude=NULL)
> d1
 [1] A    B    <NA> <NA> B    C    A    B    C    A    B    C    A    B C  
 A    B    C    A    B    C    A    B    C    A    B    C    A    B    C 
Levels: A B C <NA>
> table(b,d1)
   d1
b    A  B  C <NA>
  A  9  0  0    1
  B  0 10  0    0
  C  0  0  9    1

regards
Petr



r-help-bounces at stat.math.ethz.ch napsal dne 23.05.2007 17:39:49:

> I want to use table() to show NA values with factor variables. Using
> the set up from the help page, I have:
> 
> > b <- factor(rep(c("A","B","C"), 10))
> > d <- factor(rep(c("A","B","C"), 10), levels=c("A","B","C","D","E"))
> > is.na(d) <- 3:4
> > table(b, d)
>    d
> b    A  B  C  D  E
>   A  9  0  0  0  0
>   B  0 10  0  0  0
>   C  0  0  9  0  0
> > 
> 
> All of which is fine. But how can I get table() --- or some other
> function --- to include the observations which are NA for d? This does
> not do what I want (although I can see how it does what it is
> documented to do).
> 
> > table(b, d, exclude = NULL)
>    d
> b    A  B  C  D  E
>   A  9  0  0  0  0
>   B  0 10  0  0  0
>   C  0  0  9  0  0
> > 
> 
> Note that this dilemma only arises with factor variables. With numeric
> variables, things work differently.
> 
> > a <- c(1, 1, 2, 2, NA, 3); b <- c(2, 1, 1, 1, 1, 1); table(a, b)
>    b
> a   1 2
>   1 1 1
>   2 2 0
>   3 1 0
> > table(a, b, exclude = NULL)
>       b
> a      1 2
>   1    1 1
>   2    2 0
>   3    1 0
>   <NA> 1 0
> > 
> 
> How can I get similar behavior with factor variables?
> 
> 
> Thanks,
> 
> Dave Kane
> 
> > R.version
>                _ 
> platform       i686-pc-linux-gnu 
> arch           i686 
> os             linux-gnu 
> system         i686, linux-gnu 
> status 
> major          2 
> minor          5.0 
> year           2007 
> month          04 
> day            23 
> svn rev        41293 
> language       R 
> version.string R version 2.5.0 (2007-04-23)
> >
> 
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