Write the regular expression that matches date in format dd.mm.yyyy where dd - day, mm - month, yyyy - year like 2019 or 19

The regular expression that matches dates in the format dd.mm.yyyy, where dd represents the day, mm represents the month, and yyyy represents the year, is:

^(0?[1-9]|[1-2][0-9]|3[0-1])\.(0?[1-9]|1[0-2])\.([0-9]{4}|[0-9]{2})$

This expression matches dates with two digits for the day (01-31), two digits for the month (01-12), and either 2 or 4 digits for the year (00-99 or 0000-9999).

The first group `(0?[1-9]|[1-2][0-9]|3[0-1])` matches the day, allowing for a leading zero for single-digit days. The second group `(0?[1-9]|1[0-2])` matches the month, also allowing for a leading zero for single-digit months. The third group `([0-9]{4}|[0-9]{2})` matches the year, allowing for either a 2-digit or 4-digit year.

This expression ensures that the date is in the correct format, with the day before the month and the year at the end, separated by dots.