C# Dictionary.Remove用法及代码示例

此方法用于从字典中删除具有指定键的值。

用法:

public bool Remove (TKey key);

返回值：如果成功找到并删除了该元素，则此方法返回true；否则，此方法返回true。否则返回false。如果在Dictionary中找不到 key ，则此方法返回false。

异常：如果键为null，则此方法将提供ArgumentNullException。

以下示例程序旨在说明上述方法的使用：

示例1:

// C# code to remove the entry with 
// the specified key from the Dictionary 
using System; 
using System.Collections.Generic; 
  
class GFG { 
  
    // Driver code 
    public static void Main() 
    { 
  
        // Create a new dictionary of 
        // strings, with string keys. 
        Dictionary<string, string> myDict =  
          new Dictionary<string, string>(); 
  
        // Adding key/value pairs in myDict 
        myDict.Add("Australia", "Canberra"); 
        myDict.Add("Belgium", "Brussels"); 
        myDict.Add("Netherlands", "Amsterdam"); 
        myDict.Add("China", "Beijing"); 
        myDict.Add("Russia", "Moscow"); 
        myDict.Add("India", "New Delhi"); 
  
        // To get count of key/value pairs in myDict 
        Console.WriteLine("Total key/value pairs"+ 
              " in myDict are : " + myDict.Count); 
  
        // Remove the entry with the specified  
        // key from the Dictionary 
        myDict.Remove("Russia"); 
  
        Console.WriteLine("After remove operation"); 
  
        // To get count of key/value pairs in myDict 
        Console.WriteLine("Total key/value pairs"+ 
              " in myDict are : " + myDict.Count); 
    } 
}

输出：

Total key/value pairs in myDict are : 6
After remove operation
Total key/value pairs in myDict are : 5

示例2:

// C# code to remove the entry with 
// the specified key from the Dictionary 
using System; 
using System.Collections.Generic; 
  
class GFG { 
  
    // Driver code 
    public static void Main() 
    { 
  
        // Create a new dictionary of 
        // strings, with string keys. 
        Dictionary<int, int> myDict =  
           new Dictionary<int, int>(); 
  
        // Adding key/value pairs in myDict 
        myDict.Add(9, 8); 
        myDict.Add(3, 4); 
        myDict.Add(4, 7); 
        myDict.Add(1, 7); 
  
        // To get count of key/value pairs in myDict 
        Console.WriteLine("Total key/value pairs "+ 
                "in myDict are : " + myDict.Count); 
  
        // Remove the entry with the specified 
        // key from the Dictionary 
        myDict.Remove(9); 
  
        Console.WriteLine("After remove operation"); 
  
        // To get count of key/value pairs in myDict 
        Console.WriteLine("Total key/value pairs in"+ 
                    " myDict are : " + myDict.Count); 
    } 
}

输出：

Total key/value pairs in myDict are : 4
After remove operation
Total key/value pairs in myDict are : 3

参考：

https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2.remove?view=netframework-4.7.2

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注：本文由纯净天空筛选整理自rupesh_rao大神的英文原创作品 C# | Dictionary.Remove Method。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。