Levels Attribute for Factor Objects.

USAGE:

levels(x) <-  value 

ARGUMENTS:

x
An object inheriting from class "factor".
value
New levels. The length of value must equal the current number of levels for x. If the new levels in value are not unique, the old levels will be merged into the unique new levels. Note that in this case the numeric codes; i.e., codes(x), will change as will the length of the levels attribute.
This is a method for the function levels<-() for objects inheriting from class factor.

SEE ALSO:

(which is called when non-unique levels are assigned)