本文是小编为大家收集整理的关于带有分组和条件结果的linq查询的处理/解决方法，可以参考本文帮助大家快速定位并解决问题，中文翻译不准确的可切换到English标签页查看源文。
问题描述
我对我之前问过的一个类似问题有一个补充.我有一个结构如下的汽车类型列表:
class Car
{
public string Make { get; set; }
public string Model { get; set; }
public string SecondHand { get; set; }
public int AccidentCount { get; set; }
public int MaintenanceCount { get; set; }
}
List<Car> cars = new List<Car>()
{
new Car(){Make = "Mercedes", Model = "E-200", SecondHand ="N", AccidentCount = 1 ,MaintenanceCount = 0},
new Car(){Make = "Mercedes", Model = "E-200", SecondHand ="N", AccidentCount = 1 ,MaintenanceCount = 1},
new Car(){Make = "Mercedes", Model = "E-200", SecondHand ="Y", AccidentCount = 1 ,MaintenanceCount = 1},
new Car(){Make = "Mercedes", Model = "E-180", SecondHand ="N", AccidentCount = 0 ,MaintenanceCount = 1},
new Car(){Make = "Mercedes", Model = "E-180", SecondHand ="N", AccidentCount = 1 ,MaintenanceCount = 1}
};
我在查询的输出中需要的是 2 列用于 Make 和 Model，通过对它们进行分组，得到 2 列中的 AccidentCount 和 MaintenanceCount 的总和，最后如果给定模型输出"Y"有任何"SecondHand"值"Y"" 否则为 "N".
上面的输出应该是:
Make Model AccidentCount MaintenanceCount SecondHand Mercedes E-200 3 2 Y Mercedes E-180 1 2 N
推荐答案
我在查询输出中需要的是 2 列，通过对它们进行分组，分别用于 Make 和 Model，
cars.GroupBy(c=> new {c.Make,c.Model})
<块引用>在 2 列中获取 AccidentCount 和 MaintenanceCount 的总和
AccidentCount = g.Sum(c=>c.AccidentCount), MaintenanceCount = g.Sum(c=>c.MaintenanceCount)<块引用>
最后，如果给定模型输出"Y"有任何"SecondHand"值"Y"，否则为"N".
SecondHand = g.Any(c=> c.SecondHand=="Y") ? "Y" : "N"
最终查询如下所示:
cars.GroupBy(c=> new {c.Make,c.Model})
.Select(g=> new Car {
Make = g.Key.Make,
Model = g.Key.Model,
AccidentCount = g.Sum(c=>c.AccidentCount),
MaintenanceCount = g.Sum(c=>c.MaintenanceCount),
SecondHand = g.Any(c=> c.SecondHand=="Y") ? "Y" : "N"
});
问题描述
I have an addition to a similar question I have asked before. I have a list of car type structured like below :
class Car
{
public string Make { get; set; }
public string Model { get; set; }
public string SecondHand { get; set; }
public int AccidentCount { get; set; }
public int MaintenanceCount { get; set; }
}
List<Car> cars = new List<Car>()
{
new Car(){Make = "Mercedes", Model = "E-200", SecondHand ="N", AccidentCount = 1 ,MaintenanceCount = 0},
new Car(){Make = "Mercedes", Model = "E-200", SecondHand ="N", AccidentCount = 1 ,MaintenanceCount = 1},
new Car(){Make = "Mercedes", Model = "E-200", SecondHand ="Y", AccidentCount = 1 ,MaintenanceCount = 1},
new Car(){Make = "Mercedes", Model = "E-180", SecondHand ="N", AccidentCount = 0 ,MaintenanceCount = 1},
new Car(){Make = "Mercedes", Model = "E-180", SecondHand ="N", AccidentCount = 1 ,MaintenanceCount = 1}
};
What i need in output of query is 2 columns for Make and Model by grouping them, get sum of AccidentCount and MaintenanceCount in 2 columns and finally if there is any "SecondHand" value"Y" for a given Model output "Y" otherwise "N".
Output for above should be :
Make Model AccidentCount MaintenanceCount SecondHand Mercedes E-200 3 2 Y Mercedes E-180 1 2 N
推荐答案
What i need in output of query is 2 columns for Make and Model by grouping them,
cars.GroupBy(c=> new {c.Make,c.Model})
get sum of AccidentCount and MaintenanceCount in 2 columns
AccidentCount = g.Sum(c=>c.AccidentCount), MaintenanceCount = g.Sum(c=>c.MaintenanceCount)
and finally if there is any "SecondHand" value"Y" for a given Model output "Y" otherwise "N".
SecondHand = g.Any(c=> c.SecondHand=="Y") ? "Y" : "N"
The final query looks like this:
cars.GroupBy(c=> new {c.Make,c.Model})
.Select(g=> new Car {
Make = g.Key.Make,
Model = g.Key.Model,
AccidentCount = g.Sum(c=>c.AccidentCount),
MaintenanceCount = g.Sum(c=>c.MaintenanceCount),
SecondHand = g.Any(c=> c.SecondHand=="Y") ? "Y" : "N"
});
更多相关问答
联系站长