as_factor               Convert input to a factor
fct                     Create a factor
fct_anon                Anonymise factor levels
fct_c                   Concatenate factors, combining levels
fct_collapse            Collapse factor levels into manually defined
                        groups
fct_count               Count entries in a factor
fct_cross               Combine levels from two or more factors to
                        create a new factor
fct_drop                Drop unused levels
fct_expand              Add additional levels to a factor
fct_inorder             Reorder factor levels by first appearance,
                        frequency, or numeric order
fct_lump                Lump uncommon factor levels together into
                        "other"
fct_match               Test for presence of levels in a factor
fct_na_value_to_level   Convert between 'NA' values and 'NA' levels
fct_other               Manually replace levels with "other"
fct_recode              Change factor levels by hand
fct_relabel             Relabel factor levels with a function,
                        collapsing as necessary
fct_relevel             Reorder factor levels by hand
fct_reorder             Reorder factor levels by sorting along another
                        variable
fct_rev                 Reverse order of factor levels
fct_shift               Shift factor levels to left or right, wrapping
                        around at end
fct_shuffle             Randomly permute factor levels
fct_unify               Unify the levels in a list of factors
fct_unique              Unique values of a factor, as 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
