016 LINQ Sum

Sum() method return the calculated sum of numeric items in the collection .Below example is the example of Sum method of LINQ query.

Example
-----------------------------------
using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

           class Program

           {

                      static void Main(string[] args)

                      {

                             int[] marks = { 10, 20, 30, 40, 50, 60 };

                             int sumOfMarks = (from x in marks select x).Sum();

                             Console.WriteLine("The Sum is :" + sumOfMarks.ToString());

                             Console.ReadKey();

                      }

         }

}

//The Sum is :210
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Below example is the example of Sum method of Lambda query on a array.

Example
-------------------------------------------

using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

      class Program

       {

                static void Main(string[] args)

                {

                      int[] marks = { 10, 20, 30, 40, 50, 60 };

                           double sumOfMarks = marks.Sum(a=>a);

                           Console.WriteLine("The Sum is :" + sumOfMarks.ToString());

                           Console.ReadKey();

                }

      }

}

//The Sum is :210

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Below example is the example of Sum method of LINQ query on a collections.
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using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

                       class Program

                       {

                           static void Main(string[] args)

                            {

                               IList<student> myList = new List<student>()

                              {

                                new student { name = "John1", roll = 121, age = 5 },

                                new student { name = "John2", roll = 122, age = 6 },

                                new student { name = "John3", roll = 123, age = 7 },

                                new student { name = "John4", roll = 124, age = 8 },

                                new student { name = "John5", roll = 125, age = 9 },

                                new student { name = "John6", roll = 126, age = 10 },

                                new student { name = "John7", roll = 127, age = 11 },

                                new student { name = "John8", roll = 128, age = 17 },

                                new student { name = "John9", roll = 129, age = 18 },

                                new student { name = "John10", roll = 1210, age = 19 },

                                new student { name = "John11", roll = 1211, age = 20 }

                              };

                             var sumOfAge = myList.Sum(a => a.age);

                             Console.WriteLine("The Sum is :" + sumOfAge.ToString());

                              Console.ReadKey();

                          }

            }

}

public class student

{

           public string name { get; set; }

           public int roll { get; set; }

           public int age { get; set; }

};

--------------------------------------------------------

Below example is the example of Sum method of Lambda query on a collcetions.
---------------------------------------------------

using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

class Program

{

        static void Main(string[] args)

         {

                    IList<student> myList = new List<student>()

                   {

                         new student { name = "John1", roll = 121, age = 5 },

                         new student { name = "John2", roll = 122, age = 6 },

                         new student { name = "John3", roll = 123, age = 7 },

                         new student { name = "John4", roll = 124, age = 8 },

                         new student { name = "John5", roll = 125, age = 9 },

                         new student { name = "John6", roll = 126, age = 10 },

                         new student { name = "John7", roll = 127, age = 11 },

                         new student { name = "John8", roll = 128, age = 17 },

                         new student { name = "John9", roll = 129, age = 18 },

                        new student { name = "John10", roll = 1210, age = 19 },

                        new student { name = "John11", roll = 1211, age = 20 }

                };

                var sumOfAge = myList.Max(a => a.age);

                 Console.WriteLine("The Sum is :" + sumOfAge.ToString());

                  Console.ReadKey();

               }

     }

}

//The Maximum is :60

public class student

{

         public string name { get; set; }

         public int roll { get; set; }

        public int age { get; set; }

};

015 LINQ Skip

The Skip() method skips the specified number of element  from first element and returns rest of the elements.

Example
-----------------------------------------------
using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

                    class Program

                     {

                         static void Main(string[] args)

                          {

                             int[] marks = { 10, 20, 30, 40, 50, 60 };

                             var newList = marks.Skip(2);

                             foreach (var str in newList)

                            Console.WriteLine(str);

                            Console.ReadKey();

                       }

              }

}

//30

//40

//50

//60

-------------------------------------------- 

SkipWhile() method skip elements the till the specified condition meet . SkipWhile() returns a new collection that includes all the remaining elements that condition does not meet.
-------------------------------------------------------

using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

           class Program

            {

                    static void Main(string[] args)

                     {

                      int[] marks = { 10, 20, 30, 40, 50, 60 };

                      var newList = marks.SkipWhile(s => s < 40); ;

                      foreach (var str in newList)

                      Console.WriteLine(str);

                      Console.ReadKey();

                 }

        }

}

//40

//50

//60

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The Take()  method returns the specified number of elements from starting element to specified number of element.

----------------------------------------------------

using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

              class Program

              {

                static void Main(string[] args)

                 {

                    int[] marks = { 10, 20, 30, 40, 50, 60 };

                   var newList = marks.Take(2);

                   foreach (var str in newList)

                   Console.WriteLine(str);

                  Console.ReadKey();

             }

       }
}

//10

//20

----------------------------------

The TakeWhile() extension method returns elements of collection untill specified condition is true.
------------------------------------------

using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

         class Program

         {

                    static void Main(string[] args)

                    {

                        int[] marks = { 10, 20, 30, 40, 50, 60 };

                       var newList = marks.TakeWhile(s => s) <40 font="">

                       foreach (var str in newList)

                       Console.WriteLine(str);

                       Console.ReadKey();

                 }

         }

}

//10

//20

//30

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014 LINQ Nth Record

Finding N th record is very common query.It is asked during interview as well as useful during practical application.LINQ facilitate to find N th record of a collection.Below is the example.

-----------------------------------------------------------

using System;

using System.Collections.Generic;

using System.Data.SqlClient;

using System.Data.Sql;

using System.Data;

using System.Linq;

using System.Collections;

using System.Xml;

using System.Xml.Linq;

using System.IO;

namespace ConsoleApplication1

{

           class Program

           {

              static void Main(string[] args)

             {

                 var students = new student[]

                      {

                                new student{name = "John1",roll=123,age=12},

                                new student{name = "John2",roll=124,age=13},

                                new student{name = "John3",roll=125,age=14},

                                new student{name = "John4",roll=126,age=15},

                                new student{name = "John5",roll=127,age=16},

                                new student{name = "John6",roll=128,age=17},

                                new student{name = "John7",roll=129,age=18}

                     };

Console.WriteLine("*************LINQ nth record(Lamba Expression)***********/");

                int n = 3;

                var query = students.ElementAtOrDefault(n - 1);

                Console.WriteLine("Name :{0} ,Age :{1},Roll :{2}", query.name, query.age, query.roll);

                Console.ReadKey();

            }

       }

}

public class student

{

          public string name { get; set; }

          public int roll { get; set; }

          public int age { get; set; }

}

*************LINQ nth record(Lamba Expression)***********/
Name :John3 ,Age :14,Roll :125

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