List Count of Duplicate Names in LINQ

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
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.

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