How to Merge Two Dictionaries in C# - Step by Step Examples

How to Merge Two Dictionaries in C# ?

Answer

To merge two dictionaries in C#, you can use the `Union` method from the `System.Linq` namespace or iterate through one dictionary and add its elements to the other dictionary using the `Add` method. This allows you to combine the key-value pairs from both dictionaries.

✐ Examples

1 Merging Two Dictionaries Using `Union`

We can merge two dictionaries in C# using the `Union` method from the `System.Linq` namespace. This example demonstrates how to declare and initialize two dictionaries, use the `Union` method to merge them, and print the merged dictionary.

For example,

We start by including the necessary namespaces: using System.Collections.Generic; and using System.Linq;.
We declare and initialize two dictionaries named firstDict and secondDict with integer keys and string values.
We use the `Union` method to merge the dictionaries.
We convert the result to a dictionary using the `ToDictionary` method.
We print the merged dictionary.

C# Program

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main()
    {
        // Declare and initialize two dictionaries
        Dictionary<int, string> firstDict = new Dictionary<int, string>
        {
            {1, "One"},
            {2, "Two"}
        };

        Dictionary<int, string> secondDict = new Dictionary<int, string>
        {
            {3, "Three"},
            {4, "Four"}
        };

        // Merge the dictionaries using Union
        Dictionary<int, string> mergedDict = firstDict
            .Union(secondDict)
            .ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

        // Print the merged dictionary
        Console.WriteLine("Merged dictionary:");
        foreach (var kvp in mergedDict)
        {
            Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, kvp.Value);
        }
    }
}

Output

Merged dictionary:
Key: 1, Value: One
Key: 2, Value: Two
Key: 3, Value: Three
Key: 4, Value: Four

2 Merging Two Dictionaries Using `Add` Method

We can merge two dictionaries in C# by iterating through one dictionary and adding its elements to the other dictionary using the `Add` method. This example demonstrates how to declare and initialize two dictionaries, iterate through the second dictionary to add its elements to the first dictionary, and print the merged dictionary.

For example,

We start by including the necessary namespace: using System.Collections.Generic;.
We declare and initialize two dictionaries named firstDict and secondDict with integer keys and string values.
We iterate through the second dictionary to add its elements to the first dictionary using the `Add` method.
We print the merged dictionary.

C# Program

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Declare and initialize two dictionaries
        Dictionary<int, string> firstDict = new Dictionary<int, string>
        {
            {1, "One"},
            {2, "Two"}
        };

        Dictionary<int, string> secondDict = new Dictionary<int, string>
        {
            {3, "Three"},
            {4, "Four"}
        };

        // Merge the dictionaries by adding elements from secondDict to firstDict
        foreach (var kvp in secondDict)
        {
            firstDict.Add(kvp.Key, kvp.Value);
        }

        // Print the merged dictionary
        Console.WriteLine("Merged dictionary:");
        foreach (var kvp in firstDict)
        {
            Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, kvp.Value);
        }
    }
}

Output

Merged dictionary:
Key: 1, Value: One
Key: 2, Value: Two
Key: 3, Value: Three
Key: 4, Value: Four

Summary

In this tutorial, we learned How to Merge Two Dictionaries in C# language with well detailed examples.

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How to Merge Two Dictionaries in C# - Step by Step Examples