dates <- c("2016-04-20", "1977-08-08", "not a date", "2016",
"76-03-02", "2012-06-30", "2015-01-21 19:58")
isodate <- "([0-9]{4})-([0-1][0-9])-([0-3][0-9])"
re_match(text = dates, pattern = isodate)
# The same with named groups
isodaten <- "(?[0-9]{4})-(?[0-1][0-9])-(?[0-3][0-9])"
re_match(text = dates, pattern = isodaten)
Run the code above in your browser using DataCamp Workspace