List Count of Duplicate Names in LINQ

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If you have a Generic list with Employee Information and want to take a count of the Employees having the same name, here's how to do so:

C#

    protected void Page_Load(object sender, EventArgs e)

    {

    List<Employee> empList = new List<Employee>();

    empList.Add(new Employee() { ID = 1, FName = "John", Age=23, Sex='M'  });

    empList.Add(new Employee() { ID = 2, FName = "Mary", Age = 25, Sex = 'F' });

    empList.Add(new Employee() { ID = 3, FName = "Amber", Age = 23, Sex = 'M' });

    empList.Add(new Employee() { ID = 4, FName = "Kathy", Age=25, Sex='M'});

    empList.Add(new Employee() { ID = 5, FName = "Lena", Age=27, Sex='F'});

    empList.Add(new Employee() { ID = 6, FName = "John", Age = 28, Sex = 'M' });

    empList.Add(new Employee() { ID = 7, FName = "Kathy", Age = 27, Sex = 'F' });

    empList.Add(new Employee() { ID = 8, FName = "John", Age = 28, Sex = 'M' });

 

    var dup = empList

        .GroupBy(x => new { x.FName })

        .Select(group => new { Name = group.Key, Count = group.Count() })

        .OrderByDescending(x => x.Count);

        foreach (var x in dup)

        {

            Response.Write(x.Count + " " + x.Name);

        }

    }

 

    class Employee

    {

        public int ID { get; set; }

        public string FName { get; set; }

        public int Age { get; set; }

        public char Sex { get; set; }

    }

VB.NET

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

        Dim empList As New List(Of Employee)()

        empList.Add(New Employee() With {.ID = 1, .FName = "John", .Age = 23, .Sex = "M"c})

        empList.Add(New Employee() With {.ID = 2, .FName = "Mary", .Age = 25, .Sex = "F"c})

        empList.Add(New Employee() With {.ID = 3, .FName = "Amber", .Age = 23, .Sex = "M"c})

        empList.Add(New Employee() With {.ID = 4, .FName = "Kathy", .Age = 25, .Sex = "M"c})

        empList.Add(New Employee() With {.ID = 5, .FName = "Lena", .Age = 27, .Sex = "F"c})

        empList.Add(New Employee() With {.ID = 6, .FName = "John", .Age = 28, .Sex = "M"c})

        empList.Add(New Employee() With {.ID = 7, .FName = "Kathy", .Age = 27, .Sex = "F"c})

        empList.Add(New Employee() With {.ID = 8, .FName = "John", .Age = 28, .Sex = "M"c})

 

        Dim dup = empList _

        .GroupBy(Function(x) New With {Key x.FName}) _

        .Select(Function(group) New With {Key .Name = group.Key, Key .Count = group.Count()}) _

        .OrderByDescending(Function(x) x.Count)

        For Each x In dup

            ' Use x.count and x.Name

        Next x

    End Sub

 

    Friend Class Employee

        Private privateID As Integer

        Public Property ID() As Integer

            Get

                Return privateID

            End Get

            Set(ByVal value As Integer)

                privateID = value

            End Set

        End Property

        Private privateFName As String

        Public Property FName() As String

            Get

                Return privateFName

            End Get

            Set(ByVal value As String)

                privateFName = value

            End Set

        End Property

        Private privateAge As Integer

        Public Property Age() As Integer

            Get

                Return privateAge

            End Get

            Set(ByVal value As Integer)

                privateAge = value

            End Set

        End Property

        Private privateSex As Char

        Public Property Sex() As Char

            Get

                Return privateSex

            End Get

            Set(ByVal value As Char)

                privateSex = value

            End Set

        End Property

    End Class

End Class

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About The Author

Suprotim Agarwal, Developer Technologies MVP (Microsoft Most Valuable Professional) is the founder and contributor for DevCurry, DotNetCurry and SQLServerCurry. He is the Chief Editor of a Developer Magazine called DNC Magazine. He has also authored two Books - 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook.

Follow him on twitter @suprotimagarwal.