C# list select orderby

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WebMar 31, 2024 · var olderThan25Query = from p in people where p.Age > 25 orderby p.Age select p; Query syntax, also known as “comprehension syntax,” is inspired by SQL and functional languages like Haskell. WebC# 返回新的LINQ对象,c#,list,linq,linq-to-sql,C#,List,Linq,Linq To Sql,我想写LINQ，它返回给我一个新对象（字符串，int）包含：字符串（职位名称） int（位置计数）输出： PositionA 8 PostionB 12 PostionC 13 以下是我到目前为止的情况： public List TestL() //or IEnumerable? { var q1 = TestList.GroupBy(s => s.Postion.ToUpper()) .

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WebNov 21, 2008 · public static IQueryable OrderBy (this IQueryable source, string ordering, params object [] values) { var type = typeof (T); var property = type.GetProperty (ordering); var parameter = Expression.Parameter (type, "p"); var propertyAccess = Expression.MakeMemberAccess (parameter, property); var orderByExp = … WebJun 6, 2024 · int resA = list.QuickSelect (2, (x, y) => Comparer.Default.Compare (y, x)); int resB = list.QuickSelect (list.Count - 1 - 2); Now... Normally the QuickSelect would select the nth lowest element. We reverse it in two ways: For resA we create a reverse comparer based on the default int comparer. dominican republic comes under which country

c# - Select Multiple Fields from List in Linq - Stack Overflow

WebJul 22, 2013 · var dict = reportList .GroupBy (x => x.Type) .ToDictionary (y => y.Key, z => z.OrderBy (a => a.Lost).ToList ()); // note the ToList call or in this way: var dict = reportList.OrderBy (a => a.Lost) .GroupBy (x => x.Type) .ToDictionary (y => y.Key, z => z); // here we order then we group, // since GroupBy guarantees to preserve the original order WebJul 7, 2011 · So if I assume you want to sort by the child name that comes first lexicographically, your solution would be the following (@Paul was close on this one, but you need to specify the property you are sorting by): context. Parents. OrderBy (p => p. Children. OrderBy (c => c.Name).Select (c => c.Name).FirstOrDefault () ); WebAs you can see - enumerating goes in order provided by source enumerable (list, on which we are calling Distinct ). Hashset is used only for determining whether we already returned such element or not. If not, we are returning it, else - continue enumerating on source. dominican republic country area

Sort a List by a Field in C# Delft Stack

c# - OrderBy().Last() or OrderByDescending().First() performance ...

WebSep 2, 2011 · orders = orders.OrderBy (z => z.ordered).ToList (); Note that this "no side effects" approach is prevalent throughout LINQ - none of the operators change the collection they're called on; they return a view onto that collection of some form (filtered, projected etc). If you want to sort a List in place you can use List.Sort. WebJan 30, 2024 · This is the alternate method for sorting a list in ascending order. We’ll just call the list name created in the preceding code block by using the method OrderBy () … city of anniston permitsWebApr 29, 2016 · list1.GroupBy (item => new { Counter = item.Counter, SrvID = item.SrvID }) .Select (group => new { ID = group.First ().ID, Counter = group.Key.Counter, SrvID = group.Key.SrvID, FirstName = group.First ().FirstName}) .OrderBy (item => item.ID); Share Improve this answer Follow answered Feb 3, 2012 at 17:50 vc 74 36.7k 7 70 87 1 city of anoka electrical permit

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C# list select orderby

WebApr 12, 2024 · 二、FirstOrDefault ()方法. FirstOrDefault ()表示取集合的第一个元素。. 如果集合为空，且集合元素是引用类型，则返回null。. 如果集合为空，且集合元素是值类型，则返回默认值。. GTboy100. 实例分享 C#中 Explicit和Implicit用法. 01-21. 今天在Review一个老项目的时候，看到一 ... WebJul 22, 2010 · 1111. If you need to sort the list in-place then you can use the Sort method, passing a Comparison delegate: objListOrder.Sort ( (x, y) => x.OrderDate.CompareTo (y.OrderDate)); If you prefer to create a new, sorted sequence rather than sort in-place then you can use LINQ's OrderBy method, as mentioned in the other answers.

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WebAug 13, 2016 · Select returns IEnumerable so if you want all the LastName s in items then: var b = items.Select (s => s ["PrimaryContact"].LastName); Otherwise if you want only of one of them then after the Select use FirstOrDefault: var b = items.Select (s => s ["PrimaryContact"]).FirstOrDefault ().LastName; Share Improve this answer Follow WebSep 15, 2024 · C# string[] words = { "the", "quick", "brown", "fox", "jumps" }; IEnumerable query = from word in words orderby word.Substring (0, 1) …

Web我正在嘗試從兩個不同的數據庫表中訪問數據，然后使用c 中的linq將它們連接在兩個字段上。我相信我有一個邏輯上合理的整體工作方法。我遇到的部分問題是我在加入它們之前從兩個表中過濾數據，因為這些表有太多的數據而且會導致崩潰。主要問題是，對於其中一個表，我只需要提取當前時間 ... WebNov 2, 2013 · You need to assign the result of that query back to your variable: in LINQ lingo. string [] words = { "bac", "abc", "cab" }; var sortedWords = from w in words …

WebJul 27, 2015 · c# - OrderBy ().Last () or OrderByDescending ().First () performance - Stack Overflow OrderBy ().Last () or OrderByDescending ().First () performance Ask Question Asked 11 years, 9 months ago Modified 16 days ago Viewed 36k times 47 I know that this probably is micro-optimization, but still I wonder if there is any difference in using WebJun 10, 2016 · LINQ query to select top five. var list = from t in ctn.Items where t.DeliverySelection == true && t.Delivery.SentForDelivery == null orderby t.Delivery.SubmissionDate select t;

WebJun 10, 2015 · You want to sort the list on the numeric part, treated as a number. We'll tell OrderBy to order on that part, by splitting the string on the first space, converting the first part parts [0] to an int and sort the list on that value. No need to use Select, storing the original value and such. Just a simple OrderBy on the original List.

WebOrderBy OrderBy sorts the values of a collection in ascending or descending order. It sorts the collection in ascending order by default because ascending keyword is optional here. Use descending keyword to sort collection in descending order. Example: OrderBy in … dominican republic considered internationalWebMay 4, 2016 · context.Entities .AsEnumerable () // Continue as LINQ to objects .OrderBy (e => e.Date) .Select (e => e.Name) .Distinct () ... you'll see that the sort order is preserved in the distinct result. LINQ to objects clearly has a different strategy than LINQ to Entities. OrderBy at the end of the statement would have made both results equal. city of anoka jobs mnWebYou need to choose a Property to sort by and pass it as a lambda expression to OrderByDescending like: .OrderByDescending (x => x.Delivery.SubmissionDate); Really, though the first version of your LINQ statement should work. Is t.Delivery.SubmissionDate actually populated with valid dates? Share Improve this answer Follow dominican republic customs food productsWebJan 28, 2014 · 6. There's an awesome piece of code that does a great job when it comes to natural sorting. Its name is AlphanumComparator. Sample code: var ordered = Database.Cars.ToList ().OrderBy (c => c.ModelString, new AlphanumComparator ()); Note that the list must be in memory. dominican republic dating agencyhttp://duoduokou.com/csharp/16796641592650350892.html city of anoka city codeWebJan 17, 2013 · The only operations which change the ordering are OrderBy/OrderByDescending/ThenBy/ ThenByDescending - and even then, those are stable for equally ordered elements. Of course, many operations will filter out some elements, but the elements which are returned will be in the same order. From Jon … dominican republic curfew changeWebJul 13, 2024 · Start by ordering each row: C# IEnumerable> rlist = list.Select ( lst => lst.OrderBy (i => i).ToList () ); Then, order by the values at index #0 in each row: C# List> sortedList = = rlist.OrderBy (lst => lst … city of anoka mayor