[R] table() of a factor

Robin Hankin rksh1 at cam.ac.uk
Tue Jun 29 12:59:18 CEST 2010


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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