relextract.py 文件源码

def _join(lst, sep=' ', untag=False):
    """
    Join a list into a string, turning tags tuples into tag strings or just words.
    :param untag: if ``True``, omit the tag from tagged input strings.
    :type lst: list
    :rtype: str
    """
    try:
        return sep.join(lst)
    except TypeError:
        if untag:
            return sep.join(tup[0] for tup in lst)
        from nltk.tag import tuple2str
        return sep.join(tuple2str(tup) for tup in lst)