How to Iterate over Entries (Key-Value Pairs) in a Dictionary in C#

How to Iterate over Entries (Key-Value Pairs) in a Dictionary in C# ?

Answer

To iterate over the entries (key-value pairs) in a dictionary in C#, you can use a `foreach` loop to loop through the `KeyValuePair` objects in the dictionary. This allows you to access both the key and the value of each entry.

✐ Examples

1 Iterating over Entries Using a `foreach` Loop

We can iterate over the entries in a dictionary in C# using a `foreach` loop. This example demonstrates how to loop through the entries of a dictionary and print each key-value pair.

For example,

We start by including the necessary namespace: using System.Collections.Generic;.
We declare and initialize a dictionary named myDictionary with integer keys and string values.
We use a `foreach` loop to iterate over the entries in the dictionary.
We print each key-value pair inside the loop.

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"}
        };

        // Iterate over the entries in the dictionary
        Console.WriteLine("Entries in the dictionary:");
        foreach (KeyValuePair<int, string> kvp in myDictionary)
        {
            Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, kvp.Value);
        }
    }
}

Output

Entries in the dictionary:
Key: 1, Value: One
Key: 2, Value: Two
Key: 3, Value: Three

2 Iterating over Entries and Performing Operations on Values

We can iterate over the entries in a dictionary in C# using a `foreach` loop and perform operations on the values. This example demonstrates how to loop through the entries of a dictionary, modify the values, and print each key-value pair.

For example,

We start by including the necessary namespace: using System.Collections.Generic;.
We declare and initialize a dictionary named myDictionary with integer keys and string values.
We use a `foreach` loop to iterate over the entries in the dictionary.
Inside the loop, we modify the value associated with each key and print the modified key-value pair.

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"}
        };

        // Iterate over the entries in the dictionary and modify values
        Console.WriteLine("Modified entries in the dictionary:");
        foreach (KeyValuePair<int, string> kvp in myDictionary)
        {
            string modifiedValue = kvp.Value.ToUpper();
            Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, modifiedValue);
        }
    }
}

Output

Modified entries in the dictionary:
Key: 1, Value: ONE
Key: 2, Value: TWO
Key: 3, Value: THREE

Summary

In this tutorial, we learned How to Iterate over Entries (Key-Value Pairs) in a Dictionary in C# language with well detailed examples.

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