Three useful functions to parse and format dates.
parse_iso_8601 recognizes and parses all valid ISO
8601 date and time formats. It can also be used as an ISO 8601
validator.
parse_date can parse a date when you don't know
which format it is in. First it tries all ISO 8601 formats.
Then it tries git's versatile date parser. Lastly, it tries
as.POSIXct.
format_iso_8601 formats a date (and time) in
a specific ISO 8601 format.
Useful links: