__ATTR中的.attr
时间: 2024-06-15 22:09:02 浏览: 13
在Python中,__ATTR是一种特殊的命名约定,用于表示类的私有属性。私有属性是指只能在类内部访问的属性,外部无法直接访问或修改。通过在属性名前添加双下划线,可以将属性定义为私有属性。
私有属性的存在主要是为了封装类的内部实现细节,防止外部直接访问和修改类的属性,从而提高代码的安全性和可维护性。
尽管私有属性不能直接访问,但可以通过定义公有方法来间接地访问和修改私有属性。这种方式称为封装,它可以控制对类的属性的访问权限,并提供更加灵活和安全的操作方式。
相关问题
def __getattr__(self, attr): if attr in self.meters: return self.meters[attr] if attr in self.__dict__: return self.__dict__[attr] raise AttributeError("'{}' object has no attribute '{}'".format( type(self).__name__, attr))
这段代码是`MetricLogger`类的一个特殊方法`__getattr__`,用于在访问对象的属性时进行处理。
当访问一个属性时,如果该属性存在于`self.meters`字典中,则返回字典中对应的值。这意味着可以通过直接访问`MetricLogger`对象的属性来获取相应指标的`SmoothedValue`对象。
如果属性不存在于`self.meters`字典中,但存在于`self.__dict__`字典中(即对象的其他属性),则返回`self.__dict__[attr]`。
如果既不在`self.meters`字典中,也不在`self.__dict__`字典中,则抛出一个`AttributeError`异常,指示该对象没有该属性。
总而言之,`__getattr__`方法允许通过直接访问对象的属性来获取指标的`SmoothedValue`对象,并提供了属性不存在时的异常处理。
SELECT bs.report_no, bs.sample_id, bs.test_id, bs.service_type, bs.sample_name, bs.total_fee, bs.receivable_fee, bs.sample_no, bs.ranges, bs.grade, bs.sample_remark AS remark, bs.factory, bs.item_name, bs.apply_dept, bs.specification, bs.factory_number, bs.calibrat_point, bs.mandatory_flag, bs.inspection_type, bs.report_org_name, bs.plan_complete_date, bs.standard_instrument_name, bs.bleeding_site_name, bs.arrive_date, DATEDIFF( bs.plan_complete_date, NOW()) AS surplus_days, bs.order_no, bs.order_type, bs.customer_name, bs.order_id, bs.business_type, bs.group_id, bs.group_name, bs.item_id, bs.is_merge, bs.pass_time, bs.audit_time, bs.report_id, bs.compile_time, bs.generate_time, bs.pass_user_name, bs.audit_user_name, bs.compile_user_name, bs.report_state, bs.is_just_certificate, bs.label_price, bs.labor_cost, bs.product_type, bs.batch_number, bs.original_number, bs.type_no, bs.template_id, bs.template_version, bs.standard_instrument_id, bs.standard_instrument_name, bs.report_query_code, bs.test_user_id, bs.test_user_name, bs.test_time, bs.review_user_id, bs.review_user_name, bs.review_time, bs.or_number, bs.test_result, bs.test_result_text, bs.test_date, bs.test_address, bs.result_value, bs.unit, bs.test_dept_id, bs.test_dept_name, bs.sample_mass, bs.form, bs.color, bs.clarity, bs.amplification_detection, bs.precious_metal, bs.remarks, bs.photo, bs.identifying_code, bs.diamond_quality, bs.hand_ring, bs.craft, bs.instrument_photo, bs.customer_item_basis, bs.quality_photo, bs.check_point, bs.check_code, bs.mass_unit, bs.manufacturer_name, bs.manufacturer_addr, bs.result_sample_describe AS sampleDescribe, bs.test_rule AS metalRuleIdsStr, bsa.attach_id FROM view_sample_info bs JOIN bus_sample_report bsr ON bs.report_id = bsr.id JOIN bus_sample sa ON bsr.sample_id = sa.id JOIN bus_sample_attr bsa ON sa.id = bsa.id 需要按照bs.report_no 的整数来从小到大进行排序
你可以使用以下SQL语句来按照bs.report_no的整数值从小到大进行排序:
```sql
SELECT
bs.report_no,
bs.sample_id,
bs.test_id,
bs.service_type,
bs.sample_name,
bs.total_fee,
bs.receivable_fee,
bs.sample_no,
bs.ranges,
bs.grade,
bs.sample_remark AS remark,
bs.factory,
bs.item_name,
bs.apply_dept,
bs.specification,
bs.factory_number,
bs.calibrat_point,
bs.mandatory_flag,
bs.inspection_type,
bs.report_org_name,
bs.plan_complete_date,
bs.standard_instrument_name,
bs.bleeding_site_name,
bs.arrive_date,
DATEDIFF(bs.plan_complete_date, NOW()) AS surplus_days,
bs.order_no,
bs.order_type,
bs.customer_name,
bs.order_id,
bs.business_type,
bs.group_id,
bs.group_name,
bs.item_id,
bs.is_merge,
bs.pass_time,
bs.audit_time,
bs.report_id,
bs.compile_time,
bs.generate_time,
bs.pass_user_name,
bs.audit_user_name,
bs.compile_user_name,
bs.report_state,
bs.is_just_certificate,
bs.label_price,
bs.labor_cost,
bs.product_type,
bs.batch_number,
bs.original_number,
bs.type_no,
bs.template_id,
bs.template_version,
bs.standard_instrument_id,
bs.standard_instrument_name,
bs.report_query_code,
bs.test_user_id,
bs.test_user_name,
bs.test_time,
bs.review_user_id,
bs.review_user_name,
bs.review_time,
bs.or_number,
bs.test_result,
bs.test_result_text,
bs.test_date,
bs.test_address,
bs.result_value,
bs.unit,
bs.test_dept_id,
bs.test_dept_name,
bs.sample_mass,
bs.form,
bs.color,
bs.clarity,
bs.amplification_detection,
bs.precious_metal,
bs.remarks,
bs.photo,
bs.identifying_code,
bs.diamond_quality,
bs.hand_ring,
bs.craft,
bs.instrument_photo,
bs.customer_item_basis,
bs.quality_photo,
bs.check_point,
bs.check_code,
bs.mass_unit,
bs.manufacturer_name,
bs.manufacturer_addr,
bs.result_sample_describe AS sampleDescribe,
bs.test_rule AS metalRuleIdsStr,
bsa.attach_id
FROM
view_sample_info bs
JOIN bus_sample_report bsr ON bs.report_id = bsr.id
JOIN bus_sample sa ON bsr.sample_id = sa.id
JOIN bus_sample_attr bsa ON sa.id = bsa.id
ORDER BY CAST(bs.report_no AS UNSIGNED) ASC;
```
这将按照bs.report_no的整数值从小到大对结果进行排序。
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