nlevels(x)
nlevels returns the number of levels which its argument has. If the argument is not a factor NA is returned. The actual factor levels (if they exist) can be obtained with the levels function. See Also levels.
NA is returned. The actual factor levels (if they exist) can be obtained with the levels function. See Also levels.
The actual factor levels (if they exist) can be obtained with the levels function. See Also levels.
levels function. See Also levels.
levels.