def format_value(index, value):
    """格式化数据"""
    if value == '':
        return ''
    if value is not None:
        value = float(value)
        divisor = index['divisor']
        offset = index['offset']
        low_limit = index['low_limit']
        up_limit = index['up_limit']
        if divisor:
            value /= divisor
        if offset:
            value -= offset
        # 保留两位小数
        value = round(value, 3)
        if low_limit is not None and up_limit is not None:  # 上下限都存在
            if low_limit <= value <= up_limit:
                return value
        elif low_limit is not None and up_limit is None:  # 下限存在
            if low_limit <= value:
                return value
        elif up_limit is not None and low_limit is None:  # 上限存在
            if value <= up_limit:
                return value
        else:  # 都不存在
            return value
        # 不在范围舍弃数据
        return ''
    else:
        return ''