[R] recode according to old levels

[Andreas Wittmann]

Dear R-users,

i try to recode a factor according to old levels

F <- factor(sample(c(rep("A", 4), rep("B",2), rep("C",5))))

recode(F, "levels(F)[c(1,3)]='X'; else='Y'")

i tried to work with eval or expression around levels(F)[c(1,3)], but 
nothing seems to work.


Many thanks if anyone could tell me what i've missed and what's the 
problem here.

best regards

Andreas