def _collapse_attributes(self, line, header, indexes):
        """Combine attributes in multiple columns into single named tuple.
        """
        names = []
        vals = []
        pat = re.compile("[\W]+")
        for i in indexes:
            names.append(pat.sub("_", self._clean_header(header[i])))
            vals.append(line[i])
        Attrs = collections.namedtuple('Attrs', names)
        return Attrs(*vals)