Linq101-Restriction

using System;
using System.Linq;

namespace Linq101
{
    class Restriction
    {
        /// <summary>
        /// This sample uses where to find all elements of an array less than 5.
        /// </summary>
        public void Linq1()
        {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

            var query = from n in numbers
                        where n < 5
                        select n;

            Console.WriteLine("Numbers < 5 :");
            foreach (var number in query)
            {
                Console.WriteLine(number);
            }
        }

        /// <summary>
        /// This sample uses where to find all products that are out of stock.
        /// </summary>
        public void Linq2()
        {
            var productList = Data.GetProductList();

            var query = from product in productList
                        where product.UnitsInStock == 0
                        select product;

            Console.WriteLine("Sold out products:");
            foreach (var product in query)
            {
                Console.WriteLine("{0} is sold out!", product.ProductName);
            }
        }

        /// <summary>
        /// This sample uses where to find all products that are in stock and cost more than 3.00 per unit.
        /// </summary>
        public void Linq3()
        {
            var productList = Data.GetProductList();

            var query = from product in productList
                        where product.UnitsInStock > 0 && product.UnitPrice > 3.00M
                        select product;

            Console.WriteLine("In-stock products that cost more than 3.00:");
            foreach (var product in query)
            {
                Console.WriteLine("{0} is in stock and cost more than 3.00", product.ProductName);
            }
        }

        /// <summary>
        /// This sample uses where to find all customers in Washington and then uses the resulting sequence to drill down into their orders.
        /// </summary>
        public void Linq4()
        {
            var customerList = Data.GetCustomerList();

            var query = from customer in customerList
                        where customer.Region == "WA"
                        select customer;

            Console.WriteLine("Cutomers from Washington and their orders:");
            foreach (var customer in query)
            {
                Console.WriteLine("Customer {0}:{1}", customer.CustomerID, customer.CompanyName);
                foreach (var order in customer.Orders)
                {
                    Console.WriteLine("    Order {0}:{1}", order.OrderID, order.OrderDate);
                }
            }
        }

        /// <summary>
        /// This sample demonstrates an indexed Where clause that returns digits whose name is shorter than their value.
        /// </summary>
        public void Linq5()
        {
            string[] digits = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };

            var query = digits.Where((digit, index) => digit.Length < index);

            Console.WriteLine("Short digits:");
            foreach (var digit in query)
            {
                Console.WriteLine("The word {0} is shorter than its value.", digit);
            }
        }
    }
}