How to Filter Items of a Set based on a Condition in C# - Step by Step Examples

How to Filter Items of a Set based on a Condition in C# ?

Answer

To filter items of a set based on a condition in C#, you can use LINQ (Language Integrated Query) to apply a filtering predicate and create a new set from the filtered items.


✐ Examples

1 Filtering Numbers Greater Than 5

In this example,

  1. We create a set named numberSet using the HashSet class, which contains integer values 1, 5, 10, 15, and 20.
  2. We use LINQ to filter the numbers greater than 5 using the Where method and a lambda expression as the filtering condition.
  3. We create a new set named filteredSet using the HashSet constructor with the filtered items from the LINQ query.
  4. Finally, we iterate through filteredSet and print each filtered item to the console.

C# Program

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

class Program
{
    static void Main()
    {
        HashSet<int> numberSet = new HashSet<int> { 1, 5, 10, 15, 20 };

        var filteredSet = new HashSet<int>(numberSet.Where(x => x > 5));

        foreach (var num in filteredSet)
        {
            Console.WriteLine(num);
        }
    }
}

Output

10
15
20

2 Filtering Strings Containing 'a'

In this example,

  1. We create a set named stringSet using the HashSet class, which contains string values "apple", "banana", "cherry", "date", and "grape".
  2. We use LINQ to filter the strings containing the letter 'a' using the Where method and a lambda expression as the filtering condition.
  3. We create a new set named filteredStringSet using the HashSet constructor with the filtered items from the LINQ query.
  4. Finally, we iterate through filteredStringSet and print each filtered string to the console.

C# Program

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

class Program
{
    static void Main()
    {
        HashSet<string> stringSet = new HashSet<string> { "apple", "banana", "cherry", "date", "grape" };

        var filteredStringSet = new HashSet<string>(stringSet.Where(s => s.Contains("a")));

        foreach (var str in filteredStringSet)
        {
            Console.WriteLine(str);
        }
    }
}

Output

apple
banana
grape

Summary

In this tutorial, we learned How to Filter Items of a Set based on a Condition in C# language with well detailed examples.


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