C# |获取一个包含哈希表

中的键的集合

原文:https://www . geesforgeks . org/c-sharp-get-an-I collection-包含哈希表中的键/

哈希表。钥匙属性 用于获取一个集合，该集合包含 哈希表 中的钥匙。

语法:

public virtual System.Collections.ICollection Keys { get; }

返回值:该属性返回一个包含哈希表中键的 ICollection。

注:

  • ICollection 中的键顺序未指定。
  • 检索该属性的值是一个 O(1)操作。

以下程序说明了上述属性的使用:

例 1:

// C# code to get an ICollection containing
// the keys in the Hashtable.
using System;
using System.Collections;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a Hashtable
        Hashtable myTable = new Hashtable();

        // Adding elements in Hashtable
        myTable.Add("4", "Even");
        myTable.Add("9", "Odd");
        myTable.Add("5", "Odd and Prime");
        myTable.Add("2", "Even and Prime");

        // Get a collection of the keys.
        ICollection c = myTable.Keys;

        // Displaying the contents
        foreach(string str in c)
            Console.WriteLine(str + ": " + myTable[str]);
    }
}

Output:

5: Odd and Prime
9: Odd
2: Even and Prime
4: Even

例 2:

// C# code to get an ICollection containing
// the keys in the Hashtable.
using System;
using System.Collections;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a Hashtable
        Hashtable myTable = new Hashtable();

        // Adding elements in Hashtable
        myTable.Add("India", "Country");
        myTable.Add("Chandigarh", "City");
        myTable.Add("Mars", "Planet");
        myTable.Add("China", "Country");

        // Get a collection of the keys.
        ICollection c = myTable.Keys;

        // Displaying the contents
        foreach(string str in c)
            Console.WriteLine(str + ": " + myTable[str]);
    }
}

Output:

Chandigarh: City
India: Country
China: Country
Mars: Planet

参考:

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