Regex get last two digits of year

Question

I must use regex in order to get the last two digits of a year but only when 4 digits exist. I have the following regex which works perfectly when there is 4 digits. Example 20

Answer 1

You can use this regex.

^(?(?=\d{4}$)..(\d{2}))$

Working demo

This regex uses an IF clause, so if the string is 4 digits then captures the last two.