LINQ Element Operators

Posted on by Sharath Raju

In LINQ, Element Operators are helpful to find the first or the last element of a list/collection and can also be used to fetch an element based on its index value.

The following are the different types of element operators available in LINQ.

Topics

  • First
  • FirstOrDefault
  • Last
  • LastOrDefault
  • ElementAt
  • ElementAtOrDefault
  • Single
  • SingleOrDefault

LINQ First Operator

First Operator can be used to fetch the first element from a list/collection.

outList=my_Datasource.First()

LINQ First Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            String[] my_Items = { "Morning", "Afternoon", "Evening", "Night"};
            //Trying to fetch the first element of the list...
            String result = my_Items.First();
            
            Console.WriteLine(result);
            Console.ReadLine(); 
        }
    }
}
Output:
Morning

LINQ First Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim my_List As String() = {"Morning", "Afternoon", "Evening", "Night"}
  'Trying to fetch the first element of the list...
  Dim result As String = my_List.First()
  
  Console.WriteLine(result)
  Console.ReadLine()
  End Sub
End Module
Output:
Morning

LINQ FirstOrDefault Operator

FirstOrdefault Operator can be used to fetch the first element from a list/collection and in case if there are no values in that list/collection it will return a default value.

Example:
Int default value is 0
Boolean default value is False

outList=my_Datasource.FirstOrDefault()

LINQ FirstOrDefault Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            Int32[] num_Items1 = {10, 20, 30, 40, 50};
            Int32[] num_Items2 = { };
            //Trying to fetch the first element of the list...
            Int32 result1 = num_Items1.FirstOrDefault();
            Int32 result2 = num_Items2.FirstOrDefault();
            
            Console.WriteLine("Result1 : {0}", result1);
            Console.WriteLine("Result2 : {0}", result2);
            Console.ReadLine();
        }
    }
}
Output:
Result1 : 10
Result2 : 0

LINQ FirstOrDefault Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim num_Items1 As Int32() = {10, 20, 30, 40, 50}
  Dim num_Items2 As Int32() = {}
  'Trying to fetch the first element of the list...
  Dim result1 As String = num_Items1.FirstOrDefault()
  Dim result2 As String = num_Items2.FirstOrDefault()
  
  Console.WriteLine("Result1 : {0}", result1)
  Console.WriteLine("Result2 : {0}", result2)
  Console.ReadLine()
  End Sub
End Module
Output:
Result1 : 10
Result2 : 0

LINQ Last Operator

Last Operator can be used to fetch the last element from a list/collection.

outList=my_Datasource.Last()

LINQ Last Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            String[] my_Items = { "Morning", "Afternoon", "Evening", "Night"};
            //Trying to fetch the last element of the list...
            String result = my_Items.Last();
            
            Console.WriteLine(result);
            Console.ReadLine(); 
        }
    }
}
Output:
Night

LINQ Last Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim my_List As String() = {"Morning", "Afternoon", "Evening", "Night"}
  'Trying to fetch the last element of the list...
  Dim result As String = my_List.Last()
  
  Console.WriteLine(result)
  Console.ReadLine()
  End Sub
End Module
Output:
Night

LINQ LastOrDefault Operator

LastOrdefault Operator can be used to fetch the last element from a list/collection and in case if there are no values in that list/collection it will return a default value.

Example:
Int default value is 0
Boolean default value is False

outList=my_Datasource.LastOrDefault()

LINQ LastOrDefault Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            Int32[] num_Items1 = {10, 20, 30, 40, 50};
            Int32[] num_Items2 = { };
            //Trying to fetch the last element of the list...
            Int32 result1 = num_Items1.LastOrDefault();
            Int32 result2 = num_Items2.LastOrDefault();
            
            Console.WriteLine("Result1 : {0}", result1);
            Console.WriteLine("Result2 : {0}", result2);
            Console.ReadLine();
        }
    }
}
Output:
Result1 : 50
Result2 : 0

LINQ LastOrDefault Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim num_Items1 As Int32() = {10, 20, 30, 40, 50}
  Dim num_Items2 As Int32() = {}
  'Trying to fetch the last element of the list...
  Dim result1 As String = num_Items1.LastOrDefault()
  Dim result2 As String = num_Items2.LastOrDefault()
  
  Console.WriteLine("Result1 : {0}", result1)
  Console.WriteLine("Result2 : {0}", result2)
  Console.ReadLine()
  End Sub
End Module
Output:
Result1 : 50
Result2 : 0

LINQ ElementAt Operator

ElementAt Operator can be used to fetch an element from a list/collection based on the specified index.

In the list datatype, the index starts from zero.

outList=my_Datasource.ElementAt()

LINQ ElementAt Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            String[] my_Items = { "Morning", "Afternoon", "Evening", "Night"};
            //Trying to fetch the element of the list based on index number...
            String result = my_Items.ElementAt(1);
            
            Console.WriteLine(result);
            Console.ReadLine(); 
        }
    }
}
Output:
Afternoon

LINQ ElementAt Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim my_List As String() = {"Morning", "Afternoon", "Evening", "Night"}
  'Trying to fetch the element of the list based on index number...
  Dim result As String = my_List.ElementAt(1)
  
  Console.WriteLine(result)
  Console.ReadLine()
  End Sub
End Module
Output:
Afternoon

LINQ ElementAtOrDefault Operator

ElementAtOrdefault Operator can be used to fetch an element from a list/collection based on the specified index.and in case if that index is not valid, it will return a default value.

Example:
Int default value is 0
Boolean default value is False

outList=my_Datasource.ElementAtOrDefault()

LINQ ElementAtOrDefault Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            Int32[] num_Items1 = {10, 20, 30, 40, 50};
            Int32[] num_Items2 = { };
            //Trying to fetch the element of the list based on index number...
            Int32 result1 = num_Items1.ElementAtOrDefault(1);
            Int32 result2 = num_Items2.ElementatOrDefault(1);
            
            Console.WriteLine("Result1 : {0}", result1);
            Console.WriteLine("Result2 : {0}", result2);
            Console.ReadLine();
        }
    }
}
Output:
Result1 : 20
Result2 : 0

LINQ ElementAtOrDefault Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim num_Items1 As Int32() = {10, 20, 30, 40, 50}
  Dim num_Items2 As Int32() = {}
  'Trying to fetch the element of the list based on index number...
  Dim result1 As String = num_Items1.ElementAtOrDefault()
  Dim result2 As String = num_Items2.ElementAtOrDefault()
  
  Console.WriteLine("Result1 : {0}", result1)
  Console.WriteLine("Result2 : {0}", result2)
  Console.ReadLine()
  End Sub
End Module
Output:
Result1 : 20
Result2 : 0

LINQ Single Operator

Single Operator can be used to fetch a single element from a list/collection that actually satisfies a given condition

If the collection has got more than one element in it or no elements in it, then it will throw an exception.

outList=my_Datasource.Single()

LINQ Single Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            String[] my_Items = { "Morning", "Afternoon", "Evening", "Night"};
            //Trying to fetch the single element of the list...
            String result = my_Items.Where(x=>x.Contains("Ni")).Single();
            
            Console.WriteLine(result);
            Console.ReadLine(); 
        }
    }
}
Output:
Night

LINQ Single Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim my_List As String() = {"Morning", "Afternoon", "Evening", "Night"}
  'Trying to fetch the single element of the list...
  Dim result As String = my_Lists.Where(Function(x) x.Contains("Ni")).Single()
  
  Console.WriteLine(result)
  Console.ReadLine()
  End Sub
End Module
Output:
Night

LINQ SingleOrDefault Operator

SingleOrDefault Operator can be used to fetch a single element from a list/collection that actually satisfies a given condition

If the collection has got more than one element in it or no elements in it, then it will return a default value.

Example:
Int default value is 0
Boolean default value is False

outList=my_Datasource.SingleOrDefault()

LINQ SingleOrDefault Operator Example using C#

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

namespace LinqExamplesCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            Int32[] num_Items1 = {10, 20, 30, 40, 50};
            Int32[] num_Items2 = { };
            //Trying to fetch a single value from the list...
            Int32 result1 = num_Items1.Where(x=>x>40).SingleOrDefault();
            Int32 result2 = num_Items2.Where(x=>x>50).SingleorDefault();
            
            Console.WriteLine("Result1 : {0}", result1);
            Console.WriteLine("Result2 : {0}", result2);
            Console.ReadLine();
        }
    }
}
Output:
Result1 : 50
Result2 : 0

LINQ SingleOrDefault Operator Example using Vb.Net

Module Module1
  Sub Main()
  Dim num_Items1 As Int32() = {10, 20, 30, 40, 50}
  Dim num_Items2 As Int32() = {}
  'Trying to fetch a single value from the list...
  Dim result1 As String = num_Items1.Where(Function(x) x > 40).SingleOrDefault()
  Dim result2 As String = num_Items2.Where(Function(x) x > 50).SingleorDefault()
  
  Console.WriteLine("Result1 : {0}", result1)
  Console.WriteLine("Result2 : {0}", result2)
  Console.ReadLine()
  End Sub
End Module
Output:
Result1 : 50
Result2 : 0

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Published by Sharath Raju

I am an engineer by profession and by heart :) It's been 7+ years since I have been working with software development and robotic process automation. I have implemented close to 80+ RPA processes in total by using Uipath. It is so true that someone learns more by not reading something but by practicing the skill. I have been trying to understand exactly where people who are just starting out their career struggle and understand the pain of struggling for hours trying to figure something out.I can help you with that. Having a passion to share my piece of content, I have created step-by-step easy-to-digest courses. My goal is to help you get ready for the future by learning new talents and becoming more productive by providing you with relevant and useful courses. I'm still learning and exploring my field of work :) Every feedback should be as valuable as you are to me, please feel free to reach out to me if you have any feedback, questions, or need any help.Thank You...

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