C# |替换排序列表对象中特定索引处的值
原文:https://www . geeksforgeeks . org/c-sharp-替换特定索引中的值-sortedlist-object/
排序列表。SetByIndex(Int32，Object)方法用于替换 SortedList 对象中特定索引处的值。
语法:
public virtual void SetByIndex (int index, object value);
参数:
指标:是指从零开始的指标，在这个指标上保存价值。
值:是保存到排序列表对象中的对象。该值可以是空值。
异常:如果索引超出给定排序列表对象的有效索引范围，此方法将抛出argumentout of range Exception。
以下程序说明了上述方法的使用:
例 1:
// C# code for replacing the value at a
// specific index in a SortedList object
using System;
using System.Collections;
class Geeks {
// Main Method
public static void Main(String[] args)
{
// Creating a SortedList of integers
SortedList mylist = new SortedList();
// Adding elements to SortedList
mylist.Add("First", "Ram");
mylist.Add("Second", "Shyam");
mylist.Add("Third", "Mohit");
mylist.Add("Fourth", "Rohit");
mylist.Add("Fifth", "Manish");
// Before replacing the keys
// and values of SortedList are
Console.WriteLine("----- Before Replacing -----");
Console.WriteLine("Index \t\t Keys \t\tValues");
for (int i = 0; i < mylist.Count; i++) {
Console.WriteLine("[{0}]\t\t{1}\t\t{2}", i,
mylist.GetKey(i), mylist.GetByIndex(i));
}
Console.WriteLine();
// After replacing the keys
// and values of SortedList are
Console.WriteLine("----- After Replacing -----");
// Replaces the values at
// index 1 and index 3.
mylist.SetByIndex(1, "Priyanka");
mylist.SetByIndex(3, "Ritu");
Console.WriteLine("Index \t\t Keys \t\tValues");
for (int i = 0; i < mylist.Count; i++) {
Console.WriteLine("[{0}]\t\t{1}\t\t{2}", i,
mylist.GetKey(i), mylist.GetByIndex(i));
}
}
}
输出:
----- Before Replacing -----
Index Keys Values
[0] Fifth Manish
[1] First Ram
[2] Fourth Rohit
[3] Second Shyam
[4] Third Mohit
----- After Replacing -----
Index Keys Values
[0] Fifth Manish
[1] First Priyanka
[2] Fourth Rohit
[3] Second Ritu
[4] Third Mohit
例 2: 演示了argumentout of range exception可能发生的情况
// C# code giving ArgumentOutOfRangeException
// specific index in a SortedList object
// but giving ArgumentOutOfRangeException
using System;
using System.Collections;
class Geeks {
// Main Method
public static void Main(String[] args)
{
// Creating a SortedList of integers
SortedList mylist = new SortedList();
// Adding elements to SortedList
mylist.Add("h", "Hello");
mylist.Add("g", "Geeks!");
mylist.Add("w", "Welcome");
mylist.Add("t", "to");
mylist.Add("n", "Noida");
// Before replacing the keys
// and values of SortedList are
Console.WriteLine("----- Before Replacing -----");
Console.WriteLine("Index \t\t Keys \t\tValues");
for (int i = 0; i < mylist.Count; i++) {
Console.WriteLine("[{0}]\t\t{1}\t\t{2}", i,
mylist.GetKey(i), mylist.GetByIndex(i));
}
Console.WriteLine();
// After replacing the keys
// and values of SortedList are
Console.WriteLine("----- After Replacing -----");
// Replaces the values at
// index 6 which is outside
// the range of valid indexes
// here it will give an
// ArgumentOutOfRangeException
mylist.SetByIndex(6, null);
Console.WriteLine("Index \t\t Keys \t\tValues");
for (int i = 0; i < mylist.Count; i++) {
Console.WriteLine("[{0}]\t\t{1}\t\t{2}", i,
mylist.GetKey(i), mylist.GetByIndex(i));
}
}
}
运行时错误:
未处理异常: 系统。ArgumentOutOfRangeException:索引超出范围。必须是非负的，并且小于集合的大小。 参数名称:索引
注:
- 索引序列基于排序序列。当一个元素被添加时，它会以正确的排序顺序被插入到 SortedList 中，索引也会相应地进行调整。当元素被移除时，索引也会相应地调整。因此，在从 SortedList 对象中添加和移除元素后，特定键/值对的索引可能会改变。
- 这个方法是一个 O(1)运算。
参考:
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