[R] initialize a factor vector

[Johannes Huesing]

What is the least surprising way of initializing a factor with 
predefined levels and with length 0? 
as.factor(c("eins", "zwei", "drei"))[FALSE] 
does the job but looks a bit weird.

-- 
Johannes Hüsing               There is something fascinating about science. 
                              One gets such wholesale returns of conjecture 
mailto:johannes at huesing.name  from such a trifling investment of fact.                
http://derwisch.wikidot.com         (Mark Twain, "Life on the Mississippi")