check_date_format: Check if character date is in specific format
Description
Check if character date is in specific format
Usage
check_date_format(date, format)
Arguments
date
character. Character representation of a date, e.g.
"2018-12-13"
.
format
character. strptime format the date should have, e.g.
"%Y-%m-%d"
Value
NULL. Will stop and show error message if date does not have correct
date format.