Dictionary.Clearメソッド（C＃）

C＃のDictionary.Clear（）メソッドは、Dictionary からすべてのキーと値のペアを削除します。

構文

public void Clear();

ここで、Dictionary.Clear（）メソッドを実装する例を見てみましょう-

例

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main(){
      Dictionary<string, string> dict =
      new Dictionary<string, string>();
      dict.Add("One", "John");
      dict.Add("Two", "Tom");
      dict.Add("Three", "Jacob");
      dict.Add("Four", "Kevin");
      dict.Add("Five", "Nathan");
      Console.WriteLine("Count of elements = "+dict.Count);
      Console.WriteLine("\nKey/value pairs...");
      foreach(KeyValuePair<string, string> res in dict){
         Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);
      }
      dict.Clear();
      Console.WriteLine("Cleared Key/value pairs...");
      foreach(KeyValuePair<string, string> res in dict){
         Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);
      }
      Console.WriteLine("Count of elements now = "+dict.Count);
   }
}

出力

これにより、次の出力が生成されます-

Count of elements = 5
Key/value pairs...
Key = One, Value = John
Key = Two, Value = Tom
Key = Three, Value = Jacob
Key = Four, Value = Kevin
Key = Five, Value = Nathan
Cleared Key/value pairs...
Count of elements now = 0

ここで、Dictionary.Clear（）メソッドを実装する別の例を見てみましょう-

例

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main(){
      Dictionary<string, string> dict =
      new Dictionary<string, string>();
      dict.Add("One", "John");
      dict.Add("Two", "Tom");
      dict.Add("Three", "Jacob");
      dict.Add("Four", "Kevin");
      dict.Add("Five", "Nathan");
      Console.WriteLine("Count of elements = "+dict.Count);
      dict.Add("Six", "Anne");
      dict.Add("Seven", "Katoe");
      Console.WriteLine("Count of elements (updated) = "+dict.Count);
      Console.WriteLine("Key/value pairs...");
      foreach(KeyValuePair<string, string> res in dict){
         Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);
      }
      dict.Clear();
      Console.WriteLine("Cleared Key/value pairs...");
      foreach(KeyValuePair<string, string> res in dict){
         Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);
      }
   }
}

出力

これにより、次の出力が生成されます-

Count of elements = 5
Count of elements (updated) = 7
Key/value pairs...
Key = One, Value = John
Key = Two, Value = Tom
Key = Three, Value = Jacob
Key = Four, Value = Kevin
Key = Five, Value = Nathan
Key = Six, Value = Anne
Key = Seven, Value = Katoe
Cleared Key/value pairs...