Iterate over a Dictionary in sorted order in C#

This post will discuss how to iterate over a dictionary in sorted order in C#.

The idea is to create a sorted copy of the dictionary using LINQ’s OrderBy() method. For example, the following code iterates over a Dictionary in sorted order of keys using a foreach loop.

using System;

using System.Linq;

using System.Collections.Generic;

public class Example

{

public static void Main()

{

Dictionary<string, int> dict = new Dictionary<string, int>() {

{"B", 2}, {"A", 1}, {"D", 4}, {"C", 3}

};

foreach (var kvp in dict.OrderBy(x => x.Key)) {

Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);

}

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Output:

Key = A, Value = 1
Key = B, Value = 2
Key = C, Value = 3
Key = D, Value = 4

To sort in descending order, you can use the LINQ’s OrderByDescending() method, as shown below:

using System;

using System.Linq;

using System.Collections.Generic;

public class Example

{

public static void Main()

{

Dictionary<string, int> dict = new Dictionary<string, int>() {

{"B", 2}, {"A", 1}, {"D", 4}, {"C", 3}

};

foreach (var kvp in dict.OrderByDescending(x => x.Key)) {

Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);

}

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Output:

Key = D, Value = 4
Key = C, Value = 3
Key = B, Value = 2
Key = A, Value = 1

To iterate over the dictionary in sorted order of values, you can use the Value property of each KeyValuePair<K,V> pair. The following code example demonstrates this:

using System;

using System.Linq;

using System.Collections.Generic;

public class Example

{

public static void Main()

{

Dictionary<string, int> dict = new Dictionary<string, int>() {

{"B", 2}, {"A", 1}, {"D", 4}, {"C", 3}

};

foreach (var kvp in dict.OrderBy(x => x.Value)) {

Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);

}

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Output:

Key = A, Value = 1
Key = B, Value = 2
Key = C, Value = 3
Key = D, Value = 4

That’s all about iterating over a dictionary in sorted order in C#.

Iterate over a Dictionary in sorted order in C#

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