Convert strings to ints and floats, if so specified.

def convert_ints_floats(self, flds):
        """Convert strings to ints and floats, if so specified."""
        for idx in self.idxs_float:
            flds[idx] = float(flds[idx])
        for idx in self.idxs_int:
            dig = flds[idx]
            #print 'idx={} ({}) {}'.format(idx, flds[idx], flds) # DVK
            flds[idx] = int(flds[idx]) if dig.isdigit() else dig
        for idx in self.idxs_strpat:
            hdr = self.hdr2idx.items()[idx][0]
            pat = self.strpat_hdrs[hdr]
            flds[idx] = pat.format(flds[idx])