[R] table() of a factor

[Gavin Simpson]

On Tue, 2010-06-29 at 11:59 +0100, Robin Hankin wrote:
> Hi
> 
> suppose I have a factor 'x':
> 
>  > x <- as.factor(c(rep("a",3),"b","d"))
>  > table(x)
> x
> a b d
> 3 1 1
>  >
>  >
> 
> But this is not what I want because
> I need to include the fact that the count of "c" is zero.
> 
> I can't just change the levels of x:
> 
>  > levels(x) <- c("a","b","c","d")
>  > table(x)
> x
> a b c d
> 3 1 1 0
>  >
> 
> because this records the single "d" in the original 'x' as a "c".
> 
> 
> What I want is:
> 
> a b c d
> 3 1 0 1

If you know the levels before hand (which you appear to do) then state
them when you create the factor, but use factor() rather than coerce
with as.factor():

x <- factor(c(rep("a",3),"b","d"), levels = letters[1:4])

> table(x)
x
a b c d 
3 1 0 1

> 
> How to get this from 'x'?
> (my real application has dozens of levels with complicated names).
> 
> 
> 

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