fixed                   Match fixed characters, not regular expression.
ignore.case             Ignore case of match.
invert_match            Switch location of matches to location of
                        non-matches.
perl                    Use perl regular expressions.
str_c                   Join multiple strings into a single string.
str_count               Count the number of matches in a string.
str_detect              Detect the presence or absence of a pattern in
                        a string.
str_dup                 Duplicate and concatenate strings within a
                        character vector.
str_extract             Extract first piece of a string that matches a
                        pattern.
str_extract_all         Extract all pieces of a string that match a
                        pattern.
str_length              The length of a string (in characters).
str_locate              Locate the position of the first occurence of a
                        pattern in a string.
str_locate_all          Locate the position of all occurences of a
                        pattern in a string.
str_match               Extract first matched group from a string.
str_match_all           Extract all matched groups from a string.
str_pad                 Pad a string.
str_replace             Replace first occurrence of a matched pattern
                        in a string.
str_replace_all         Replace all occurrences of a matched pattern in
                        a string.
str_split               Split up a string into a variable number of
                        pieces.
str_split_fixed         Split up a string into a fixed number of
                        pieces.
str_sub                 Extract substrings from a character vector.
str_sub_replace         Replace substrings in a character vector.
                        'str_sub<-' will recycle all arguments to be
                        the same length as the longest argument.
str_trim                Trim whitespace from start and end of string.
str_wrap                Wrap strings into nicely formatted paragraphs.
word                    Extract words from a sentence.