Attached below is a brief summary of ICU's number parsing behaviour (data collected using ICU4C 49.1.2) The following data will be parsed successfully regardless of the pattern or strict/lenient parsing mode Digits 0-9 Decimal Separator Exponent Separator Grouping separators are only permitted in the data, if specified in the pattern When in STRICT mode the following will cause a parse failure (using a pattern of "#,##0.#") Leading or doubled grouping separators ',123' and '1,,234" fail Groups of incorrect length when grouping is used '1,23' and '1234,567' fail, but '1234' passes Grouping separators used in numbers followed by exponents '1,234E5' fails, but '1234E5' and '1,234E' pass ('E' is not an exponent when not followed by a number) 'Other' characters in the pattern must be present in the data. For example, with a pattern of 'z'## :- z12 will parse successfully, 12 will only parse successfully in lenient mode. Regards Richard Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU