Per this 2022 post, base grepl with perl = TRUE is the best-looking option and avoids novel dependencies.
The mixed-case single-character variant is the first priority, then everything else is case-agnostic and can be transformed once to use a single reference table.
Filter on [:alpha:] to avoid chaff in input.
Per this 2022 post, base grepl with perl = TRUE is the best-looking option and avoids novel dependencies.
The mixed-case single-character variant is the first priority, then everything else is case-agnostic and can be transformed once to use a single reference table.
Filter on
[:alpha:]to avoid chaff in input.