Csharp/CSharp Tutorial/LINQ/Sum

Grouped Sum

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;
    }
}

Numeric Aggregates: Sum

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));
        }
    }

Sum with integers

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);
    }
}

Sum with object property

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);
    }
}

Sum with Projection

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);
    }
}

use Linq Sum to sum an array

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();
   }
}

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

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);
    }
}