Drop unused levels in a factor.

This is only a wrapper for drop.levels

dropLevels(x, reorder = TRUE, ...)

Arguments

x	object to be processed
reorder	should factor levels be reordered using gdata::reorder.factor?
...	additional arguments to 'reorder.factor'

Value

Input object without unused levels.

See also

drop.levels

Examples

f<-factor(c(NA,1,1,2),levels=c(0,1,2),labels=c('a','b','NA'))
dropLevels(f)
#> [1] <NA> b    b    NA  
#> Levels: b NA