Linq-sorting-operators

LINQの演算子の並べ替え

ソート操作を使用すると、単一または複数の属性に基づいてシーケンスの要素を並べることができます。

Operator	Description	C# Query Expression Syntax	VB Query Expression Syntax
OrderBy	The operator sort values in an ascending order	orderby	Order By
OrderByDescending	The operator sort values in a descending order	orderby …​ descending	Order By …​ Descending
ThenBy	Executes a secondary sorting in an ascending order	orderby …, …	Order By …, …
ThenByDescending	Executes a secondary sorting in a descending order	orderby …, … descending	Order By …, … Descending
Reverse	Performs a reversal of the order of the elements in a collection	Not Applicable	Not Applicable

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Operators {
   class Program {
      static void Main(string[] args) {

         int[] num = { -20, 12, 6, 10, 0, -3, 1 };

        //create a query that obtain the values in sorted order
         var posNums = from n in num
                       orderby n
                       select n;

         Console.Write("Values in ascending order: ");

        //Execute the query and display the results.

         foreach (int i in posNums)
            Console.Write(i + " \n");

            var posNumsDesc = from n in num
                              orderby n descending
                              select n;

            Console.Write("\nValues in descending order: ");

        //Execute the query and display the results.

         foreach (int i in posNumsDesc)
            Console.Write(i + " \n");

            Console.ReadLine();
      }
   }
}

VB

Module Module1

   Sub Main()

      Dim num As Integer() = {-20, 12, 6, 10, 0, -3, 1};

      Dim posNums = From n In num
                    Order By n
                    Select n;

      Console.Write("Values in ascending order: ");

      For Each n In posNums
         Console.WriteLine(n)
      Next

      Dim posNumsDesc = From n In num
                       Order By n Descending
                       Select n;

         Console.Write("Values in descending order: ");

      For Each n In posNumsDesc
         Console.WriteLine(n)

      Next
         Console.ReadLine()

   End Sub

End Module

C＃またはVBの上記のコードがコンパイルされて実行されると、次の結果が生成されます-

Values in ascending order: -20
-3
0
1
6
10
12
Values in descending order: 12
10
6
1
0
-3
-20

ThenbyおよびThenbyDescending演算子では、同じ構文を適用でき、並べ替え順序は複数の列に依存します。 優先順位は、最初に維持される列になります。