Today i had write the Regular Expression to match Italian Istat Ateco Code (formally Codice Istat) updated to Ateco-Istat 2004. The regex expression is downloadable from : http://regexlib.com/REDetails.aspx?regexp_id=1620

This is the source : \d{2}[.]{1}\d{2}[.]{1}[0-9A-Za-z]{1}

This is the match : 22.12.0|18.24.C

This is the unmatch : 22.12_D|12.56| 1A.56.1