Open In App

C# | Gets an ICollection containing the keys in the Hashtable

Improve
Improve
Improve
Like Article
Like
Save Article
Save
Share
Report issue
Report

Hashtable.Keys Property is used to get an ICollection containing the keys in the Hashtable.

Syntax:

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

Return Value: This property returns an ICollection containing the keys in the Hashtable.

Note:

  • The order of keys in the ICollection is unspecified.
  • Retrieving the value of this property is an O(1) operation.

Below programs illustrate the use of above-discussed property:

Example 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

Example 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

Reference:



Last Updated : 01 Feb, 2019
Like Article
Save Article
Previous
Next
Share your thoughts in the comments
Similar Reads