Linq group by 去重
NettetAdd a comment. 2. An alternative way to do this could be select distinct PersonId and group join with persons: var result = from id in persons.Select (x => x.PersonId).Distinct () join p2 in persons on id equals p2.PersonId into gr // apply group join here select new { PersonId = id, Cars = gr.Select (x => x.Car).ToList (), }; Nettet其实只要明白 LINQ查询操作符的Distinct、Union、Concat、Intersect、Except、Skip、Take、SkipWhile、TakeWhile、Single、SingleOrDefault、Reverse、SelectMany,Aggregate ()的使用,一些简单的操作就可以了。 合并两个数组,并去掉重复元素,然后排序 (C#) 在这简单的介绍几个关键字,Distinct、Union、Concat、Intersect …
Linq group by 去重
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Nettet三、下面介绍Linq使用Group By的常见场景 1.简单形式: var q = from p in db.Products group p by p.CategoryID into g select g; 语句描述 :Linq使用Group By按CategoryID划分产品。 说明 :from p in db.Products 表示从表中将产品对象取出来。 group p by p.CategoryID into g表示对p按CategoryID字段归类。 其结果命名为g,一旦重新命名,p … Nettet8. mar. 2024 · Language-Integrated Query (LINQ) is the name for a set of technologies based on the integration of query capabilities directly into the C# language. Traditionally, queries against data are expressed as simple strings without type checking at compile time or IntelliSense support.
Nettet17. mai 2024 · 第一种分组去重 年龄和名称进行分组,然后取第一条即可达到去重,如下: var list1 = list.GroupBy(d => new { d.Age, d.Name }) .Select(d => d.FirstOrDefault()) … Nettet其实只要明白 LINQ查询操作符的Distinct、Union、Concat、Intersect、Except、Skip、Take、SkipWhile、TakeWhile、Single、SingleOrDefault、Reverse …
Nettetvar results = persons.GroupBy( p => p.PersonId, p => p.car, (key, g) => new { PersonId = key, Cars = g.ToList() }); Basically the contents of the group (when viewed as an … NettetLINQ Group by used to group the list of collected items/data based on the particular value of the key and based on the grouping data it returns the result as the collection of …
Nettet29. des. 2024 · LINQ操作DataTable示例 方式一 var results = from myRow in myDataTable.AsEnumerable () where myRow.Field< int > ( "RowNo") == 1 select myRow; 方式二 var results = from DataRow myRow in myDataTable. Rows where (int)myRow ["RowNo"] == 1 select myRow 方式三
Nettet6. apr. 2024 · En este artículo. La agrupación es una de las capacidades más eficaces de LINQ. Los ejemplos siguientes muestran cómo agrupar datos de varias maneras: Por una sola propiedad. Por la primera letra de una propiedad de cadena. Por un intervalo numérico calculado. Por un predicado booleano u otra expresión. krystal\u0027s lunch hoursNettet16. mai 2013 · LINQ去重 狼王_ 2012-10-30 01:50:02 using (var ctx = new ReadModel.ReadEntities ()) { var pwList = new List (); try { pwList = ctx.product_whole.Where ( p => (p.p_code != null && p.p_code.IndexOf (strKeyWords) > -1) (p.p_name != null && p.p_name.IndexOf (strKeyWords) > -1) krystal\u0027s leavenworth waNettet12. apr. 2024 · 一、查阅文档 Enumerable.Distinct 方法是常用的LINQ扩展方法,属于System.Linq的Enumerable方法,可用于去除数组、集合中的重复元素,还可以自定义 … krystal\\u0027s leavenworth waNettet23. jan. 2024 · 利用Linq对集合元素合并、去重复处理. 今天写代码时,需要对一个数组对象中按一定规则合并、去重处理,不想再毫无新意手动写For循环遍历(天天写一样的代 … krystal\\u0027s menu with pricesNettet25. aug. 2024 · c# list数据去重,使用linq的GroupBy数据去重只需要三行代码模型代码 public class UserInfo { public int id { set; get; } public string name { set; get; } public int … krystal\u0027s menu and pricesNettet15. aug. 2024 · 首先,需要的功能是: Code Sub Count Fl001 1 20 Fl002 1 15 Fl001 1 10 需要使用Linq进行去重查询,只返回code相同的第一行数据即可,而使用Distinct()根 … krystal\u0027s mcdonough gaNettetGroup by in linq with sum. In above example if you notice, we have used sum function to get the sum of score, here is the piece of code again. var groupScores = from … krystal\u0027s memphis tn