[R] table() of a factor

[Felix Andrews]

Just use factor(), not levels(); you can pass a factor to factor() too.

> x <- factor(c(rep("a",3),"b","d"), levels = letters[1:5])
> table(x)
x
a b c d e
3 1 0 1 0

Cheers,
-Felix


On 29 June 2010 20:59, Robin Hankin <rksh1 at cam.ac.uk> 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
>
>
> How to get this from 'x'?
> (my real application has dozens of levels with complicated names).
>
>
>
> --
> Robin K. S. Hankin
> Uncertainty Analyst
> University of Cambridge
> 19 Silver Street
> Cambridge CB3 9EP
> 01223-764877
>
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-- 
Felix Andrews / 安福立
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