Csharp/CSharp Tutorial/LINQ/Sum

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Grouped Sum

<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text; public class MainClass {

   public static void Main() {
       List<Product> products = GetProductList();
       var categories =
          from p in products
          group p by p.Category into g
          select new { Category = g.Key, TotalUnitsInStock = g.Sum(p => p.UnitsInStock) };
       Console.Write(categories);
   }
   static List<Product> GetProductList() {
       List<Product> empTree = new List<Product>();
       empTree.Add(new Product { ProductName = "A", Category = "O", UnitPrice = 12, UnitsInStock = 5, Total = 36, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
       empTree.Add(new Product { ProductName = "B", Category = "O", UnitPrice = 2, UnitsInStock = 4, Total = 35, OrderDate = new DateTime(2005, 1, 1), Id = 2 });
       empTree.Add(new Product { ProductName = "C", Category = "O", UnitPrice = 112, UnitsInStock = 3, Total = 34, OrderDate = new DateTime(2005, 1, 1), Id = 3 });
       empTree.Add(new Product { ProductName = "D", Category = "O", UnitPrice = 112, UnitsInStock = 0, Total = 33, OrderDate = new DateTime(2005, 1, 1), Id = 4 });
       empTree.Add(new Product { ProductName = "E", Category = "O", UnitPrice = 1112, UnitsInStock = 2, Total = 32, OrderDate = new DateTime(2005, 1, 1), Id = 5 });
       empTree.Add(new Product { ProductName = "F", Category = "O", UnitPrice = 11112, UnitsInStock = 0, Total = 31, OrderDate = new DateTime(2005, 1, 1), Id = 6 });
       return empTree;
   }
   static List<Customer> GetCustomerList() {
       List<Product> empTree = new List<Product>();
       empTree.Add(new Product { ProductName = "A", Category = "O", UnitPrice = 12, UnitsInStock = 5, Total = 36, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
       empTree.Add(new Product { ProductName = "B", Category = "O", UnitPrice = 2, UnitsInStock = 4, Total = 35, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
       empTree.Add(new Product { ProductName = "C", Category = "O", UnitPrice = 112, UnitsInStock = 3, Total = 34, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
       empTree.Add(new Product { ProductName = "D", Category = "O", UnitPrice = 112, UnitsInStock = 0, Total = 33, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
       empTree.Add(new Product { ProductName = "E", Category = "O", UnitPrice = 1112, UnitsInStock = 2, Total = 32, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
       empTree.Add(new Product { ProductName = "F", Category = "O", UnitPrice = 11112, UnitsInStock = 0, Total = 31, OrderDate = new DateTime(2005, 1, 1), Id = 1 });
       List<Customer> l = new List<Customer>();
       l.Add(new Customer { CompanyName = "A", Region = "R1", UnitsInStock = 1, Orders = empTree, CustomerId = 0 });
       l.Add(new Customer { CompanyName = "B", Region = "R2", UnitsInStock = 2, Orders = empTree, CustomerId = 1 });
       l.Add(new Customer { CompanyName = "C", Region = "R3", UnitsInStock = 3, Orders = empTree, CustomerId = 2 });
       l.Add(new Customer { CompanyName = "D", Region = "R4", UnitsInStock = 4, Orders = empTree, CustomerId = 3 });
       l.Add(new Customer { CompanyName = "E", Region = "R5", UnitsInStock = 5, Orders = empTree, CustomerId = 4 });
       return l;
   }

} class Customer : IComparable<Customer> {

   public string CompanyName { get; set; }
   public string Region { get; set; }
   public List<Product> Orders { get; set; }
   public int UnitsInStock { get; set; }
   public int CustomerId { get; set; }
   public override string ToString() {
       return String.Format("Id: {0}, Name: {1}, Region: {3}", this.CustomerId, this.rupanyName, this.Region);
   }
   int IComparable<Customer>.rupareTo(Customer other) {
       if (other == null)
           return 1;
       if (this.CustomerId > other.CustomerId)
           return 1;
       if (this.CustomerId < other.CustomerId)
           return -1;
       return 0;
   }

} class Product : IComparable<Product> {

   public string ProductName { get; set; }
   public string Category { get; set; }
   public int UnitPrice { get; set; }
   public int UnitsInStock { get; set; }
   public int Total { get; set; }
   public DateTime OrderDate { get; set; }
   public int Id { get; set; }
   public override string ToString() {
       return String.Format("Id: {0}, Name: {1} , Category: {3}", this.Id, this.ProductName, this.Category);
   }
   int IComparable<Product>.rupareTo(Product other) {
       if (other == null)
           return 1;
       if (this.Id > other.Id)
           return 1;
       if (this.Id < other.Id)
           return -1;
       return 0;
   }

}</source>

Numeric Aggregates: Sum

<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text;

   class Program
   {
       static void Main(string[] args)
       {
           Random generator = new Random(0);
           int[] numbers = new int[1000];
           for (int i = 0; i < 1000; i++)
           {
               numbers[i] = generator.Next();
           }
           var queryResults = from n in numbers where n > 100 select n;
           Console.WriteLine("Sum of Numbers > 100");
           Console.WriteLine(queryResults.Sum(n => (long)n));
       }
   }</source>

Sum with integers

<source lang="csharp">using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass {

   public static void Main() {
       IEnumerable<int> ints = Enumerable.Range(1, 10);
       foreach (int i in ints)
           Console.WriteLine(i);
       int sum = ints.Sum();
       Console.WriteLine(sum);
   }

}</source>

Sum with object property

<source lang="csharp">using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class Employee {

   public int id;
   public string firstName;
   public string lastName;
   public static ArrayList GetEmployeesArrayList() {
       ArrayList al = new ArrayList();
       al.Add(new Employee { id = 1, firstName = "J", lastName = "R" });
       al.Add(new Employee { id = 2, firstName = "W", lastName = "G" });
       al.Add(new Employee { id = 3, firstName = "A", lastName = "H" });
       al.Add(new Employee { id = 4, firstName = "D", lastName = "L" });
       al.Add(new Employee { id = 101, firstName = "K", lastName = "F" });
       return (al);
   }
   public static Employee[] GetEmployeesArray() {
       return ((Employee[])GetEmployeesArrayList().ToArray(typeof(Employee)));
   }

} public class EmployeeOptionEntry {

   public int id;
   public long optionsCount;
   public DateTime dateAwarded;
   public static EmployeeOptionEntry[] GetEmployeeOptionEntries() {
       EmployeeOptionEntry[] empOptions = new EmployeeOptionEntry[] {
       new EmployeeOptionEntry { 
         id = 1, 
         optionsCount = 2, 
         dateAwarded = DateTime.Parse("1999/12/31") },
       new EmployeeOptionEntry { 
         id = 101, 
         optionsCount = 2, 
         dateAwarded = DateTime.Parse("1998/12/31") }
     };
       return (empOptions);
   }

} public class MainClass {

   public static void Main() {
       IEnumerable<EmployeeOptionEntry> options = EmployeeOptionEntry.GetEmployeeOptionEntries();
       long optionsSum = options.Sum(o => o.optionsCount);
       Console.WriteLine("The sum of the employee options is: {0}", optionsSum);
   }

}</source>

Sum with Projection

<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text; public class MainClass {

   public static void Main() {
       string[] words = { "cherry", "apple", "blueberry" };
       double totalChars = words.Sum(w => w.Length);
       Console.WriteLine("There are a total of {0} characters in these words.", totalChars);
   }

}</source>

use Linq Sum to sum an array

<source lang="csharp">using System; using System.Collections; using System.Collections.Generic; using System.Text; using System.Linq; using System.Reflection; public class MainClass{

  public static void Main(){
           int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
           var query = numbers.Sum();
  }

}</source>

use Sum to find the total of all of the numbers in an integer array.

<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text; public class MainClass {

   public static void Main() {
       int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
       double numSum = numbers.Sum();
       Console.WriteLine("The sum of the numbers is {0}.", numSum);
   }

}</source>