C# 程序在 Dictionary 中查找键

csharpprogrammingserver side programming

首先,设置一个包含元素的 Dictionary 集合。

Dictionary<int, string> d = new Dictionary<int, string>() {
   {1,"Applianes"},
   {2, "Clothing"},
   {3,"Toys"},
   {4,"Footwear"},
   {5, "Accessories"}
};

现在,假设您需要检查键 5 是否存在。为此,请使用 ContainsKey() 方法。如果找到键,则返回 True。

d.ContainsKey(5);

让我们看一下完整的代码。

示例

using System;
using System.Collections.Generic;
public class Program {
   public static void Main() {
      Dictionary<int, string> d = new Dictionary<int, string>() {
         {1,"Electronics"},
         {2, "Clothing"},
         {3,"Toys"},
         {4,"Footwear"},
         {5, "Accessories"}
      };
      foreach (KeyValuePair<int, string> ele in d) {
         Console.WriteLine("Key = {0}, Value = {1}", ele.Key, ele.Value);
      }
      Console.WriteLine("Key 5 exists? "+d.ContainsKey(5));
   }
}

输出

Key = 1, Value = Electronics
Key = 2, Value = Clothing
Key = 3, Value = Toys
Key = 4, Value = Footwear
Key = 5, Value = Accessories
Key 5 exists? True

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