Python regex '\s' does not match unicode BOM (U+FEFF)

Question

The Python re module's documentation says that when the re.UNICODE flag is set, '\s' will match:

whatever is classified as space in the Unicode character properties database.

As far I can tell, the BOM (U+FEFF) is classified as a space.

However:

re.match(u'\s', u'\ufeff', re.UNICODE)

evaluates to None.

Is this a bug in Python or am I missing something?

Answer 1

U+FEFF is not a whitespace character according to the unicode database.

Wikipedia only lists it as it is a "related character". These are similar to whitespace characters but don't have the WSpace property in the database.

None of those characters are matched by \s.