set of columns to apply transformation to. If NULL will apply
to all POSIXt columns (for messy_datetime_formats()) or Date columns (for
messy_date_formats()).
formats
A vector of any number of valid strptime() formats. Multiple
formats will be sampled at random.
Author
Jack Davison
See Also
Other Messy date(time) functions:
messy_datetime_tzones(),
split_datetimes()