[R] simple question with table()

[Berwin A Turlach]

G'day Simone,

On Sun, 30 Nov 2008 11:05:13 +0100
Simone Gabbriellini <simone.gabbriellini at gmail.com> wrote:

> my problem should be easy to fix, but I couldn't find a solution by  
> myself...
> 
> In my survey, there is a question with 14 possible answers. None of  
> the respondents choose the 13th answer, so when I table() the
> results, R says:
[...]
> 13 is missing... anyone knows how to tell table() that there are 14  
> modalities in the answers?

The easiest way is probably to turn your data into a factor with the
appropriate set of levels:

R> dat <- sample(c(1:12,14), 100, replace=TRUE)
R> table(factor(dat, levels=min(dat):max(dat)))

 1  2  3  4  5  6  7  8  9 10 11 12 13 14 
 9  5  4  7  7 11  8 10  9  8  6 11  0  5 

that was once the solution of one of my colleagues and I find it
somewhat nicer than the one I came up with:

R> rng <- min(dat):max(dat)
R> res <- colSums(outer(dat, min(dat):max(dat), "=="))
R> names(res) <- rng
R> res
 1  2  3  4  5  6  7  8  9 10 11 12 13 14 
 9  5  4  7  7 11  8 10  9  8  6 11  0  5 
 
HTH.

Best wishes,

	Berwin

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