4 ms·

The {4} is being applied to the whole group which includes a .* Isn't that correct?

• Izkata 2y ago
  Yep, and the .* means "0 or more of anything", so it's 4 or more groups that each end with a letter. They can be consecutive or not and a group can be a single letter but doesn't need to be - so whatever the failure was, it wasn't that (or the regex was typo'd here to be correct instead of what was actually on the site).
  • account42 2y ago
    The regexp still requires four letters before the last digit or special character which is a weird requirement.
    • GrantMoyer 2y ago
      The (?=…) are "lookaheads". They match the enclosed pattern without advancing the cursor.