Drop unused levels of a factor
Usage
drop_levels(x, ...)
# S3 method for data.frame
drop_levels(x, ...)
# S3 method for fact
drop_levels(x, ...)
# S3 method for factor
drop_levels(x, ...)
See also
Other factors:
as_ordered()
,
char2fact()
,
fact2char()
,
fact_na()
,
fact()