soundex.py 文件源码

def soundex(source):
    "convert string to Soundex equivalent"

    # Soundex requirements:
    # source string must be at least 1 character
    # and must consist entirely of letters
    if (not source) or (not source.isalpha()):
        return "0000"

    # Soundex algorithm:
    # 1. make first character uppercase
    # 2. translate all other characters to Soundex digits
    digits = source[0].upper() + source[1:].translate(charToSoundex)

    # 3. remove consecutive duplicates
    digits2 = digits[0]
    for d in digits[1:]:
        if digits2[-1] != d:
            digits2 += d

    # 4. remove all "9"s
    # 5. pad end with "0"s to 4 characters
    return (digits2.replace('9', '') + '000')[:4]