complete                Complete a data frame with missing combinations
                        of data.
expand                  Expand data frame to include all combinations
                        of values
extract                 Extract one column into multiple columns.
extract_numeric         Extract numeric component of variable.
fill                    Fill in missing values.
gather                  Gather columns into key-value pairs.
nest                    Nest repeated values in a list-varible.
nest_                   Standard-evaluation version of 'nest'.
replace_na              Replace missing values
separate                Separate one column into multiple columns.
seq_range               Create an evenly spaced sequence of values from
                        lowest to highest.
spread                  Spread a key-value pair across multiple
                        columns.
spread_                 Standard-evaluation version of 'spread'.
unite                   Unite multiple columns into one.
unnest                  Unnest a list column.
unnest_                 Standard-evaluation version of 'unnest'.
