## Change order of levels

Keep the values of the levels the same, but change their order. These are particularly useful for models, tables, and visualisations.

fct_relevel()

Reorder factor levels by hand

fct_inorder() fct_infreq() fct_inseq()

Reorder factors levels by first appearance, frequency, or numeric order.

fct_reorder() fct_reorder2() last2()

Reorder factor levels by sorting along another variable

fct_shuffle()

Randomly permute factor levels

fct_rev()

Reverse order of factor levels

fct_shift()

Shift factor levels to left or right, wrapping around at end

## Change value of levels

Change factor levels, while preserving order (as much as possible).

fct_anon()

Anonymise factor levels

fct_collapse()

Collapse factor levels into manually defined groups

fct_lump() fct_lump_min()

Lump together least/most common factor levels into "other"

fct_other()

Replace levels with "other"

fct_recode()

Change factor levels by hand

fct_relabel()

Automatically relabel factor levels, collapse as necessary

Leave existing data as is, but add or remove levels.

fct_expand()

fct_explicit_na()

Make missing values explicit

fct_drop()

Drop unused levels

fct_unify()

Unify the levels in a list of factors

## Combine multiple factors

fct_c()

Concatenate factors, combining levels

fct_cross()

Combine levels from two or more factors to create a new factor

## Other helpers

as_factor()

Convert input to a factor.

fct_count()

Count entries in a factor

fct_match()

Test for presence of levels in a factor

fct_unique()

Unique values of a factor

lvls_reorder() lvls_revalue() lvls_expand()

Low-level functions for manipulating levels

lvls_union()

Find all levels in a list of factors

## Data

gss_cat

A sample of categorical variables from the General Social survey