levels
of an object. This is
most useful for
factors
and
bdFactors
.
levels(x) levels(x) <- value
bdCharacter
.
x
has
levels
, then the
levels
are returned;
otherwise
NULL
.
Using
levels<-
makes sure that the length of
value
is the same as the length of
the (old) levels of
x
, but you can combine factors by giving them
the same level.
If
value
is a list and
x
is a factor, the method returns
merge.levels(x, value)
. See
merge.levels
for details on
how this may be used to combine or add levels to a factor.
levels(fuel.frame$Type[1:9]) #demonstrates drop levels(fuel.frame$Type[1:9, drop=TRUE])