C# | Get an ICollection containing the keys in HybridDictionary
HybridDictionary.Keys property is used to get an ICollection containing the keys in the HybridDictionary.
Syntax:
public System.Collections.ICollection Keys { get; }
Return Value: It returns an ICollection containing the keys in the HybridDictionary.
Below programs illustrate the use of HybridDictionary.Keys Property:
Example 1:
// C# code to get an ICollection containing // the keys in the HybridDictionary. using System; using System.Collections; using System.Collections.Specialized; class GFG { // Driver code public static void Main() { // Creating a HybridDictionary named myDict HybridDictionary myDict = new HybridDictionary(); // Adding key/value pairs in myDict myDict.Add( "A" , "Apple" ); myDict.Add( "B" , "Banana" ); myDict.Add( "C" , "Cat" ); myDict.Add( "D" , "Dog" ); myDict.Add( "E" , "Elephant" ); myDict.Add( "F" , "Fish" ); // Creating a String arr named myArr String[] myArr = new String[myDict.Count]; // copying the Keys in HybridDictionary // to a one-dimensional Array instance // at the specified index. myDict.Keys.CopyTo(myArr, 0); // To get an ICollection containing // the keys in the HybridDictionary for ( int i = 0; i < myDict.Count; i++) Console.WriteLine(myArr[i]); } } |
Output:
A B C D E F
Example 2:
// C# code to get an ICollection containing // the keys in the HybridDictionary. using System; using System.Collections; using System.Collections.Specialized; class GFG { // Driver code public static void Main() { // Creating a HybridDictionary named myDict HybridDictionary myDict = new HybridDictionary(); // Adding key/value pairs in myDict myDict.Add( "I" , "first" ); myDict.Add( "II" , "second" ); myDict.Add( "III" , "third" ); myDict.Add( "IV" , "fourth" ); myDict.Add( "V" , "fifth" ); // Creating a String arr named myArr String[] myArr = new String[myDict.Count]; // copying the Keys in HybridDictionary // to a one-dimensional Array instance // at the specified index. myDict.Keys.CopyTo(myArr, 0); // To get an ICollection containing // the keys in the HybridDictionary for ( int i = 0; i < myDict.Count; i++) Console.WriteLine(myArr[i]); } } |
Output:
I II III IV V
Note:
- The order of the values in the ICollection is unspecified, but it is the same order as the associated values in the ICollection returned by the Values method.
- The returned ICollection is not a static copy. Instead, the ICollection refers back to the keys in the original HybridDictionary. Therefore, changes to the HybridDictionary continue to be reflected in the ICollection.
- Retrieving the value of this property is an O(1) operation.
Reference:
- https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.hybriddictionary.keys?view=netframework-4.7.2
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