How to Iterate over Keys in a Dictionary in C# - Step by Step Examples

How to Iterate over Keys in a Dictionary in C# ?

Answer

To iterate over the keys in a dictionary in C#, you can use a `foreach` loop to loop through the `Keys` property of the `Dictionary` class from the `System.Collections.Generic` namespace. This allows you to access each key individually.

✐ Examples

1 Iterating over Keys Using a `foreach` Loop

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

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 `Keys` property of the dictionary.
We print each key 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 keys in the dictionary
        Console.WriteLine("Keys in the dictionary:");
        foreach (int key in myDictionary.Keys)
        {
            Console.WriteLine("Key: {0}", key);
        }
    }
}

Output

Keys in the dictionary:
Key: 1
Key: 2
Key: 3

2 Iterating over Keys and Accessing Corresponding Values

We can iterate over the keys in a dictionary in C# using a `foreach` loop and access the corresponding values. This example demonstrates how to loop through the keys of a dictionary and print each key along with its associated value.

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 `Keys` property of the dictionary.
Inside the loop, we access and print the value associated with each 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"}
        };

        // Iterate over the keys in the dictionary and access corresponding values
        Console.WriteLine("Keys and values in the dictionary:");
        foreach (int key in myDictionary.Keys)
        {
            string value = myDictionary[key];
            Console.WriteLine("Key: {0}, Value: {1}", key, value);
        }
    }
}

Output

Keys and values 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 Keys in a Dictionary in C# language with well detailed examples.

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How to Iterate over Keys in a Dictionary in C# - Step by Step Examples