Csharp/C Sharp/LINQ/Average

Материал из .Net Framework эксперт
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Average with int array

<source lang="csharp">

using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass {

   public static void Main() {
       IEnumerable<int> intSequence = Enumerable.Range(1, 10);
       foreach (int i in intSequence)
           Console.WriteLine(i);
       double average = intSequence.Average();
       Console.WriteLine("Here is the average:  {0}", average);
   }

}

</source>


Grouped Average

<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, AveragePrice = g.Average(p => p.UnitPrice) };
       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>


Use Average method to calculate the average value from a query

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

   int _id;
   int _year;
   double _salary;
   public int ID {
       get { return _id; }
       set { _id = value; }
   }
   public int Year {
       get { return _year; }
       set { _year = value; }
   }
   public double SalaryPaid {
       get { return _salary; }
       set { _salary = value; }
   }

} class Employee {

   int _id;
   int _idRole;
   string _lastName;
   string _firstName;
   public int ID {
       get { return _id; }
       set { _id = value; }
   }
   public int IDRole {
       get { return _idRole; }
       set { _idRole = value; }
   }
   public string LastName {
       get { return _lastName; }
       set { _lastName = value; }
   }
   public string FirstName {
       get { return _firstName; }
       set { _firstName = value; }
   }

} class Role {

   int _id;
   string role;
   public int ID {
       get { return _id; }
       set { _id = value; }
   }
   public string Role {
       get { return role; }
       set { role = value; }
   }

} public class MainClass {

   public static void Main() {
       List<Employee> people = new List<Employee> {
              new Employee { ID = 1, IDRole = 1, LastName = "A", FirstName = "B"},
              new Employee { ID = 2, IDRole = 2, LastName = "G", FirstName = "T"},
              new Employee { ID = 3, IDRole = 2, LastName = "G", FirstName = "M"},
              new Employee { ID = 4, IDRole = 3, LastName = "C", FirstName = "G"}
           };
       List<Role> roles = new List<Role> {
              new Role { ID = 1, Role = "Manager" },
              new Role { ID = 2, Role = "Developer" }
           };
       List<Salary> salaries = new List<Salary> {
              new Salary { ID = 1, Year = 2004, SalaryPaid = 10.00 },
              new Salary { ID = 1, Year = 2005, SalaryPaid = 15.00 },
              new Salary { ID = 1, Year = 2005, SalaryPaid = 15.00 }
           };
       var query = from p in people
                   join s in salaries on p.ID equals s.ID
                   where p.ID == 1
                   select s.SalaryPaid;
       Console.WriteLine("Average Salary:");
       Console.Write(query.Average());
   }

}

</source>


uses Average to get the average length of the words in the string array.

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

   public static void Main() {
       string[] words = { "ch", "a", "blue" };
       double averageLength = words.Average(w => w.Length);
       Console.WriteLine("The average word length is {0} characters.", averageLength);
   }

}

</source>


uses Average to get the average of all values of 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 averageNum = numbers.Average();
       Console.WriteLine("The average number is {0}.", averageNum);
   }

}

</source>