C# | Gets an ICollection containing the keys in the Hashtable
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:
- https://docs.microsoft.com/en-us/dotnet/api/system.collections.hashtable.keys?view=netframework-4.7.2
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