droplevels
is used to drop unused levels from factors
in a ffdf
The function droplevels
is used to drop unused levels from factors
in a ffdf
# S3 method for ffdf
droplevels(x, except = NULL, ..., inplace = FALSE)
ffdf
object
specify which columns will be excluded from dropping levels
further arguments passed to droplevels.ff
if TRUE
the columns will be physically changed,
otherwise (default) new ff
vectors will be created
ffdf
object where levels of factors are dropped