It makes sense that this is not bi-directional, because it’s for matching substrings. It should be bi-directional if both strings are of the same length, as you pointed out.

Most importantly: the original Levenshtein is bi-directional, meaning that Levenshtein(a,b) == Levenshtein(b,a)

However with your modification, this is no longer the case! In other words, FuzzyLevenshtein(a,b) != FuzzyLevenshtein(b,a)

From my experiments, it appears that FuzzyLevenshtein(a,b) can/will be a lower value when b (the target) has extra characters in its prefix/suffix.
When a (the source) has the extra characters, then the Fuzzy version is the same as the original.

Does this make sense to you? Do you agree? Thanks!

Had to look up “vbc.” Count Anything counts “all characters” and “characters (no spaces)”. The second measure is the total character count minus the number of characters for which c.isspace() returns true.

def get_multilingual_header(header_text, default=”ascii”):
    if not header_text is None:
        try:
            headers = header.decode_header(header_text)
        except HeaderParseError:
            return u”Error”

        try:
            header_sections = [unicode(text, charset if charset and charset!='unknown' else default, errors='replace') for text, charset in headers]
        except LookupError:
            header_sections = [unicode(text, default, errors='replace') for text, charset in headers]

        return u”".join(header_sections)
    else:
        return None

def decode_email(raw_email):
    raw_email = raw_email.replace(‘\r’, ‘ ‘).replace(‘\n’, ‘ ‘).replace(‘ ‘, ‘ ‘)
    if re.match(‘=\?.*?\?[QqBb]\?.*\?=$’, raw_email):
        name, email = utils.parseaddr(get_multilingual_header(raw_email))
    else:
        name, email = utils.parseaddr(raw_email)
        name = get_multilingual_header(name)
        email = get_multilingual_header(email)

    decoded_email = utils.formataddr((name, email))
    return decoded_email

This worked for all my test cases, in particular:

print decode_email(‘=?UTF-8?B?5qGD5aSqLCDpg44=?= ‘)

This is how GMail sends it these days and if you decode the whole string first you’re in trouble because decoded it contains a “,”, which means you end up with 2 email addresses