C# | Gets or sets the value in HybridDictionary with specified key
HybridDictionary.Item[Object] property is used to get or set the value associated with the specified key.
Syntax:
public object this[object key] { get; set; }
Here, key is the key whose value is to be get or set.
Return Value: The value associated with the specified key. If the specified key is not found, attempting to get it returns null, and attempting to set it creates a new entry using the specified key.
Exception: This property will give ArgumentNullException if the key is null.
Below programs illustrate the use of HybridDictionary.Item[Object] property:
Example 1:
// C# code to get or set the value // associated with the specified key // in 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( "Australia" , "Canberra" ); myDict.Add( "Belgium" , "Brussels" ); myDict.Add( "Netherlands" , "Amsterdam" ); myDict.Add( "China" , "Beijing" ); myDict.Add( "Russia" , "Moscow" ); myDict.Add( "India" , "New Delhi" ); // Displaying the key/value pairs in myDict foreach (DictionaryEntry de in myDict) { Console.WriteLine(de.Key + " " + de.Value); } // Displaying the value associated // with key "Russia" Console.WriteLine(myDict[ "Russia" ]); // Setting the value associated with key "Russia" myDict[ "Russia" ] = "Saint Petersburg" ; // Displaying the value associated // with key "Russia" Console.WriteLine(myDict[ "Russia" ]); // Displaying the value associated // with key "India" Console.WriteLine(myDict[ "India" ]); // Setting the value associated with key "India" myDict[ "India" ] = "Mumbai" ; // Displaying the value associated // with key "India" Console.WriteLine(myDict[ "India" ]); // Displaying the key/value pairs in myDict foreach (DictionaryEntry de in myDict) { Console.WriteLine(de.Key + " " + de.Value); } } } |
Output:
Australia Canberra Belgium Brussels Netherlands Amsterdam China Beijing Russia Moscow India New Delhi Moscow Saint Petersburg New Delhi Mumbai Australia Canberra Belgium Brussels Netherlands Amsterdam China Beijing Russia Saint Petersburg India Mumbai
Note:
- This property provides the ability to access a specific element in the collection by using the syntax : myCollection[key].
- A key cannot be null, but a value can.
- Retrieving the value of this property is an O(1) operation. Setting the property is also an O(1) operation.
Reference:
- https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.hybriddictionary.item?view=netframework-4.7.2
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