$.re2_matrix            Get a match group
UNANCHORED              Anchors for pattern
get_expression_size     Get pre-compiled regular expression program
                        size
get_named_groups        Return capturing names for a pre-compiled
                        regular expression.
get_number_of_groups    Return the number of capturing subpatterns
get_options             Get options of a pre-compiled regular
                        expression
get_pattern             The string specification for this RE2.
get_program_fanout      Get program fanout
get_simplify            Simplify pattern strings.
is_re2c_na              Check NA pattern
print.re2_matrix        Print information about a re2_matrix
print.re2c              Print information about a pre-compiled regular
                        expression
quote_meta              Escapes all potentially meaningful regexp
                        characters in 'unquoted'.
re2                     Create a pre-compiled regular expression
re2_count               Count the number of matches in a string.
re2_detect              Test a pattern in strings, and return boolean.
re2_extract             Extract matching patterns from a string.
re2_locate              Locate the position of patterns in a string.
re2_match               Find matched groups from strings.
re2_replace             Replace matched patterns in a string.
re2_split               Split a string into pieces.
re2_subset              Keep strings matching a pattern.
show_regex              Show regex pattern in a htmlwidget
sub_string              Extract and replace substrings from a character
                        vector.
