在 C# 中的指定索引位置从集合的末尾创建索引
在 C# 8.0 中引入了索引结构。它表示可用于索引集合或序列的类型，并且可以从开始或结束开始。您可以在索引结构提供的 FromEnd(Int32)方法的帮助下创建结束索引。此方法返回给定集合或序列末尾指定位置的索引。
语法:
public static Index FromEnd(int value);
例:1
// C# program to illustrate the
// concept of the FromEnd() Method
using System;
namespace example {
class Program {
// Main Method
static void Main(string[] args)
{
// Creating end index
// Using FromEnd() method
var in1 = Index.FromEnd(2);
var in2 = Index.FromEnd(1);
var in3 = Index.FromEnd(0);
var in4 = Index.FromEnd(6);
// Display index value
Console.WriteLine("Index position is : {0} ", in1);
Console.WriteLine("Index position is : {0} ", in2);
Console.WriteLine("Index position is : {0} ", in3);
Console.WriteLine("Index position is : {0} ", in4);
}
}
}
输出:
Index position is : ^2
Index position is : ^1
Index position is : ^0
Index position is : ^6
例 2:
// C# program to illustrate the
// concept of the FromEnd() method
using System;
namespace example {
class GFG {
// Main Method
static void Main(string[] args)
{
// Creating and initializing an array
string[] greetings = new string[] {"Hello", "Hola", "Namaste",
"Bonjour", "Ohayo", "Ahnyounghaseyo"};
// Creating end index
// Using FromEnd() method
var index_1 = Index.FromEnd(3);
var index_2 = Index.FromEnd(1);
var index_3 = Index.FromEnd(4);
var index_4 = Index.FromEnd(5);
// Displaying index and their values
Console.WriteLine("Index: {0} Value: {1}",
index_1, greetings[index_1]);
Console.WriteLine("Index: {0} Value: {1}",
index_2, greetings[index_2]);
Console.WriteLine("Index: {0} Value: {1}",
index_3, greetings[index_3]);
Console.WriteLine("Index: {0} Value: {1}",
index_4, greetings[index_4]);
}
}
}
输出:
Index: ^3 Value: Bonjour
Index: ^1 Value: Ahnyounghaseyo
Index: ^4 Value: Namaste
Index: ^5 Value: Hola
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