LINQ 中的排序运算符
排序操作允许基于一个或多个属性对序列中的元素进行排序。
| 运算符 | 描述 | C# 查询表达式语法 | VB 查询表达式语法 |
|---|---|---|---|
| OrderBy | 运算符按照升序对值进行排序 | orderby | Order By |
| OrderByDescending | 运算符按照降序对值进行排序 | orderby ... descending | Order By ... Descending |
| ThenBy | 按照升序执行二次排序 | orderby …, … | Order By …, … |
| ThenByDescending | 按照降序执行二次排序 | orderby …, … descending | Order By …, … Descending |
| Reverse | 对集合中元素的顺序进行反转 | 不适用 | 不适用 |
OrderBy、OrderByDescending 的示例 - 查询表达式
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
在 C# 或 VB 中编译并执行以上代码时,会产生以下结果 -
Values in ascending order: -20 -3 0 1 6 10 12 Values in descending order: 12 10 6 1 0 -3 -20
在 Thenby 和 ThenbyDescending 运算符中,可应用相同的语法,排序顺序将取决于多个列。优先级将是首先维护的列。
linq_query_operators.htm
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