fct_anon                Anonymise factor levels
fct_c                   Concatenate factors, unioning levels.
fct_collapse            Collapse factors into groups.
fct_count               Count entries in a factor
fct_drop                Drop unnused levels
fct_expand              Add additional levels to a factor
fct_explicit_na         Make missing values explicit
fct_inorder             Reorders levels in order of first appearance or
                        frequency.
fct_lump                Lump together least/most common levels into
                        "other".
fct_recode              Change the levels of a factor
fct_relevel             Change the order of levels in a factor
fct_reorder             Reorder the levels of a function according to
                        another variable
fct_rev                 Reverse the levels of a factor
fct_shift               Shift the order of levels of a factor
fct_shuffle             Randomly permute the levels of a factor
fct_unify               Unify the levels in a list of factors
fct_unique              Unique values of a factor
gss_cat                 A sample of categorical variables from the
                        General Social survey
lvls                    Low-level functions for manipulating levels
lvls_union              Find all levels in a list of factors
