python过滤字符串中不属于指定集合的字符的类，python字符串,# -*- coding

python过滤字符串中不属于指定集合的字符的类，python字符串,# -*- coding

# -*- coding: utf-8 -*-import setsclass Keeper(object):    def __init__(self, keep):        self.keep = sets.Set(map(ord, keep))    def __getitem__(self, n):        if n not in self.keep:            return None        return unichr(n)    def __call__(self, s):        return s.translate(self)makefilter = Keeperif __name__ == '__main__':    just_vowels = makefilter('aeiouy')    print just_vowels(u'four score and seven years ago')    # 输出: ouoeaeeyeaao    print just_vowels(u'tiger, tiger burning bright')    # 输出: ieieuii