How to Get the Value Associated with a Key in a Dictionary in C# - Step by Step Examples



How to Get the Value Associated with a Key in a Dictionary in C# ?

Answer

To get the value associated with a key in a dictionary in C#, you can use the indexer or the `TryGetValue` method of the `Dictionary` class from the `System.Collections.Generic` namespace.



✐ Examples

1 Getting the Value Associated with a Key Using the Indexer

We can get the value associated with a key in a dictionary in C# using the indexer. This example demonstrates how to retrieve the value for a specific key and print it.

For example,

  1. We start by including the necessary namespace: using System.Collections.Generic;.
  2. We declare and initialize a dictionary named myDictionary with integer keys and string values.
  3. We use the indexer to get the value associated with a key.
  4. We print the value associated with the key.

C# Program

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Declare and initialize a dictionary
        Dictionary<int, string> myDictionary = new Dictionary<int, string>
        {
            {1, "One"},
            {2, "Two"},
            {3, "Three"}
        };

        // Key to get the value for
        int keyToGet = 2;

        // Get the value associated with the key using the indexer
        string value = myDictionary[keyToGet];

        // Print the value associated with the key
        Console.WriteLine("The value associated with key {0} is '{1}'.", keyToGet, value);
    }
}

Output

The value associated with key 2 is 'Two'.

2 Getting the Value Associated with a Key Using the `TryGetValue` Method

We can get the value associated with a key in a dictionary in C# using the `TryGetValue` method. This example demonstrates how to safely retrieve the value for a specific key and print it if it exists.

For example,

  1. We start by including the necessary namespace: using System.Collections.Generic;.
  2. We declare and initialize a dictionary named myDictionary with integer keys and string values.
  3. We use the `TryGetValue` method to get the value associated with a key.
  4. We print the value associated with the key if it exists, or a message if it does not.

C# Program

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Declare and initialize a dictionary
        Dictionary<int, string> myDictionary = new Dictionary<int, string>
        {
            {1, "One"},
            {2, "Two"},
            {3, "Three"}
        };

        // Key to get the value for
        int keyToGet = 4;

        // Try to get the value associated with the key using the TryGetValue method
        if (myDictionary.TryGetValue(keyToGet, out string value))
        {
            // Print the value associated with the key
            Console.WriteLine("The value associated with key {0} is '{1}'.", keyToGet, value);
        }
        else
        {
            // Print a message if the key does not exist
            Console.WriteLine("The key {0} does not exist in the dictionary.", keyToGet);
        }
    }
}

Output

The key 4 does not exist in the dictionary.

Summary

In this tutorial, we learned How to Get the Value Associated with a Key in a Dictionary in C# language with well detailed examples.




More C# Dictionaries Tutorials

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  2. How to create a Dictionary with Initial Key-Value Pairs in C# ?
  3. How to Print a Dictionary in C# ?
  4. How to Add a Key-Value Pair to a Dictionary in C# ?
  5. How to Set a Default Value for a Key in a Dictionary in C# ?
  6. How to Update the Value for a Key in a Dictionary in C# ?
  7. How to Check if a Dictionary is Empty in C# ?
  8. How to Check if a Key Exists in a Dictionary in C# ?
  9. How to Check if a Value Exists in a Dictionary in C# ?
  10. How to Get the Value Associated with a Key in a Dictionary in C# ?
  11. How to Remove a Key-Value Pair from a Dictionary in C# ?
  12. How to Remove Key-Value Pairs from a Dictionary Based on Values in C# ?
  13. How to Clear all Key-Value Pairs from a Dictionary in C# ?
  14. How to Iterate over Keys in a Dictionary in C# ?
  15. How to Iterate over Values in a Dictionary in C# ?
  16. How to Iterate over Entries (Key-Value Pairs) in a Dictionary in C# ?
  17. How to Get the Size (Number of Key-Value Pairs) of a Dictionary in C# ?
  18. How to Convert a Dictionary to an Array of Keys in C# ?
  19. How to Convert a Dictionary to an Array of Values in C# ?
  20. How to Convert a Dictionary to an Array of Key-Value Pairs in C# ?
  21. How to Merge Two Dictionaries in C# ?
  22. How to Clone a Dictionary in C# ?
  23. How to Check if Two Dictionaries are Equal in C# ?
  24. How to Sort a Dictionary by Keys in C# ?
  25. How to Sort a Dictionary by Values in C# ?
  26. How to Filter a Dictionary Based on Keys in C# ?
  27. How to Filter a Dictionary Based on Values in C# ?
  28. How to Reduce Values in a Dictionary to a Single Value in C# ?
  29. How to Convert an Array of Key-Value Pairs to a Dictionary in C# ?
  30. How to Convert a Dictionary to a JSON String in C# ?
  31. How to Convert a JSON String to a Dictionary in C# ?
  32. How to Swap Keys and Values in a Dictionary in C# ?
  33. How to Create a Dictionary of Dictionaries in C# ?
  34. How to Iterate Over a Dictionary of Dictionaries in C# ?