Matching a group that may or may not exist

Question

My regex needs to parse an address which looks like this:

BLOOKKOKATU 20 A 773 00810 HELSINKI SUOMI
-------------------- ----- -------- -----
          1                 


        

Answer 1

Change the regex to:

(.*?)\s(\d{5})\s(.+?)\s?(FINLAND|SUOMI)?$

Making group three none greedy will let you match the optional space + country choices. If group 4 doesn't match I think it will be uninitialized rather than blank, that depends on language.