Regex for IBAN allowing for white spaces AND checking for exact length

Question

I need to check an input field for a German IBAN. The user should be allowed to leave in white spaces and input should be validated to have a starting DE

Answer 1

This is the correct regex to match DE IBAN account numbers:

DE\d{2}[ ]\d{4}[ ]\d{4}[ ]\d{4}[ ]\d{4}[ ]\d{2}|DE\d{20}

Pass:   DE89 3704 0044 0532 0130 00|||DE89370400440532013000
Fail:   DE89-3704-0044-0532-0130-00