Csharp/CSharp Tutorial/LINQ/foreach loop

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Cars going faster than 55, ordered by PetName

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml.Linq;
using System.Linq;
    class Car
    {
        public string PetName;
        public string Color;
        public int Speed;
        public string Make;
        
        public override string ToString()
        {
            return string.Format("Make={0}, Color={1}, Speed={2}, PetName={3}",Make, Color, Speed, PetName);
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Car[] myCars = new []{
                new Car{ PetName = "A", Color = "Silver", Speed = 100, Make = "BMW"},
                new Car{ PetName = "B", Color = "Black", Speed = 55, Make = "VW"},
                new Car{ PetName = "C", Color = "White", Speed = 43, Make = "Ford"}
            };
        
           
            var subset = from c in myCars where c.Speed > 55 orderby c.PetName descending select c;
            foreach (Car c in subset)
            {
                Console.WriteLine(c.ToString());
            }
        
        }
    }

Linq over array

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml.Linq;
using System.Linq;
    class Program
    {
        static void Main(string[] args)
        {
            int[] numbers = { 10, 20, 30, 40, 1, 2, 3, 8 };
            var subset = from i in numbers where i < 10 select i;
            foreach (var i in subset)
                Console.Write("Item: {0} ", i);
            Console.WriteLine("resultSet is of type: {0}", subset.GetType().Name);
            Console.WriteLine("resultSet location: {0}", subset.GetType().Assembly);
        }
    }

Linq Over ArrayList

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml.Linq;
using System.Linq;
using System.Collections;
    class Car
    {
        public string PetName;
        public string Color;
        public int Speed;
        public string Make;
    }
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList myCars = new ArrayList();  
            myCars.Add(new Car{ PetName = "Henry", Color = "Silver", Speed = 100, Make = "BMW"});
            myCars.Add(new Car{ PetName = "Clunker", Color = "Rust", Speed = 5, Make = "Yugo"});
            myCars.Add(new Car { PetName = "Melvin", Color = "White", Speed = 43, Make = "Ford" });
            IEnumerable<Car> myCarsEnum = myCars.OfType<Car>();
            // Create a query expression. 
            var fastCars = from c in myCarsEnum where c.Speed > 55 select c;
            foreach (var car in fastCars)
            {
                Console.WriteLine("{0} is going too fast!", car.PetName);
            }
        }
    }

Linq Over Array Using Sequence

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml.Linq;
using System.Linq;
    class Program
    {
        static void Main(string[] args)
        {
            string[] currentVideoGames = {"test", "this is a test", "asdf", "game 1","game 2", "game 3"};
            var subset = from g in currentVideoGames where g.Length > 6 orderby g select g;
            foreach (var s in subset)
                Console.WriteLine("Item: {0}", s);
        }
    }

Linq To Objects

using System;
using System.Text;
using System.Linq;
using System.Collections.Generic;
    class LinqToObjects
    {
        static void Main(string[] args)
        {
            string[] names = { "test", "test 1", "Am" };
            IEnumerable<string> namesOfPeople = from name in names where name.Length <= 2 select name;
            foreach (var name in namesOfPeople)
                Console.WriteLine(name);
             
        }
    }

Simple linq

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
    public class Customer
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string EmailAddress { get; set; }
        public override string ToString()
        {
            return string.Format("{0} {1}\nEmail:   {2}",FirstName, LastName, EmailAddress);
        }
    }
    public class Tester
    {
        static void Main()
        {
            List<Customer> customers = new List<Customer>{
                    new Customer { FirstName = "A", 
                                    LastName = "B",
                                    EmailAddress = "o@a.ru"},
                    new Customer { FirstName = "B", 
                                    LastName = "C",
                                    EmailAddress = "k@a.ru" },
                    new Customer { FirstName = "D", 
                                    LastName = "C",
                                    EmailAddress = "d@a.ru" },
                    new Customer { FirstName = "F", 
                                    LastName = "G",
                                    EmailAddress = "j@a.ru" },
                    new Customer { FirstName = "L", 
                                    LastName = "H",
                                    EmailAddress = "l@a.ru" }
                };
            IEnumerable<Customer> result =
                from customer in customers
                where customer.FirstName == "Donna"
                select customer;
            foreach (Customer customer in result)
                Console.WriteLine(customer.ToString());
            customers[3].FirstName = "Donna";
            foreach (Customer customer in result)
                Console.WriteLine(customer.ToString());
        }
    }

Use foreach loop to deal with the result from linq

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
    public static void Main() {
        List<Customer> customers = GetCustomerList();
        var waCustomers =
            from c in customers
            where c.Region == "R1"
            select c;
        foreach (var customer in waCustomers) {
            Console.WriteLine("Customer {0}: {1}", customer.CustomerId, customer.rupanyName);
            foreach (var order in customer.Orders) {
                Console.WriteLine(" Order {0}: {1}", order.Id, order.OrderDate);
            }
        }
    }
    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;
    }
}
Источник — «http://nfex.ru/index.php?title=Csharp/CSharp_Tutorial/LINQ/foreach_loop&oldid=6129»