数组linq

1、public void Linq1() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

            var lowNums =
                from n in numbers
                where n < 5
                select n;
       
            Console.WriteLine("Numbers < 5:");
            foreach (var x in lowNums) {
                Console.WriteLine(x);
            }
        }

2、public void Linq2() {
            List<Product> products = GetProductList();

            var soldOutProducts =
                from p in products
                where p.UnitsInStock == 0
                select p;
           
            Console.WriteLine("Sold out products:");
            foreach (var product in soldOutProducts) {
                Console.WriteLine("{0} is sold out!", product.ProductName);
            }
        }

3、public void Linq3() {
            List<Product> products = GetProductList();

            var expensiveInStockProducts =
                from p in products
                where p.UnitsInStock > 0 && p.UnitPrice > 3.00M
                select p;
           
            Console.WriteLine("In-stock products that cost more than 3.00:");
            foreach (var product in expensiveInStockProducts) {
                Console.WriteLine("{0} is in stock and costs more than 3.00.", product.ProductName);
            }
        }

4、public void Linq4() {
            List<Customer> customers = GetCustomerList();

            var waCustomers =
                from c in customers
                where c.Region == "WA"
                select c;
           
            Console.WriteLine("Customers from Washington and their orders:");
            foreach (var customer in waCustomers) {
                Console.WriteLine("Customer {0}: {1}", customer.CustomerID, customer.CompanyName);
                foreach (var order in customer.Orders) {
                    Console.WriteLine(" Order {0}: {1}", order.OrderID, order.OrderDate);
                }
            }
        }

5、public void Linq5() {
            string[] digits = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };

            var shortDigits = digits.Where((digit, index) => digit.Length < index);
       
            Console.WriteLine("Short digits:");
            foreach (var d in shortDigits) {
                Console.WriteLine("The word {0} is shorter than its value.", d);
            }
        }

6、public void Linq6() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

            var numsPlusOne =
                from n in numbers
                select n + 1;
           
            Console.WriteLine("Numbers + 1:");
            foreach (var i in numsPlusOne) {
                Console.WriteLine(i);
            }
        }

7、public void Linq7() {
            List<Product> products = GetProductList();

            var productNames =
                from p in products
                select p.ProductName;
           
            Console.WriteLine("Product Names:");
            foreach (var productName in productNames) {
                Console.WriteLine(productName);
            }
        }

8、public void Linq8() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
            string[] strings = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };

            var textNums =
                from n in numbers
                select strings[n];
           
            Console.WriteLine("Number strings:");
            foreach (var s in textNums) {
                Console.WriteLine(s);
            }          
        }

9、public void Linq9() {
            string[] words = { "aPPLE", "BlUeBeRrY", "cHeRry" };

            var upperLowerWords =
                from w in words
                select new {Upper = w.ToUpper(), Lower = w.ToLower()};

            foreach (var ul in upperLowerWords) {
                Console.WriteLine("Uppercase: {0}, Lowercase: {1}", ul.Upper, ul.Lower);
            }
        }

10、public void Linq10() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
            string[] strings = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };

            var digitOddEvens =
                from n in numbers
                select new {Digit = strings[n], Even = (n % 2 == 0)};

            foreach (var d in digitOddEvens) {
                Console.WriteLine("The digit {0} is {1}.", d.Digit, d.Even ? "even" : "odd");
            }
        }

11、public void Linq11() {
            List<Product> products = GetProductList();

            var productInfos =
                from p in products
                select new {p.ProductName, p.Category, Price = p.UnitPrice};
           
            Console.WriteLine("Product Info:");
            foreach (var productInfo in productInfos) {
                Console.WriteLine("{0} is in the category {1} and costs {2} per unit.", productInfo.ProductName, productInfo.Category, productInfo.Price);
            }
        }

12、public void Linq12() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };

            var numsInPlace = numbers.Select((num, index) => new {Num = num, InPlace = (num == index)});
       
            Console.WriteLine("Number: In-place?");
            foreach (var n in numsInPlace) {
                Console.WriteLine("{0}: {1}", n.Num, n.InPlace);
            }
        }

13、public void Linq13() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
            string[] digits = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };

            var lowNums =
                from n in numbers
                where n < 5
                select digits[n];
           
            Console.WriteLine("Numbers < 5:");
            foreach (var num in lowNums) {
                Console.WriteLine(num);
            }      
        }

14、public void Linq14() {
            int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };
            int[] numbersB = { 1, 3, 5, 7, 8 };

            var pairs =
                from a in numbersA
                from b in numbersB
                where a < b
                select new {a, b};
       
            Console.WriteLine("Pairs where a < b:");
            foreach (var pair in pairs) {
                Console.WriteLine("{0} is less than {1}", pair.a, pair.b);
            }
        }

15、public void Linq15() {
            List<Customer> customers = GetCustomerList();

            var orders =
                from c in customers
                from o in c.Orders
                where o.Total < 500.00M
                select new {c.CustomerID, o.OrderID, o.Total};
       
            ObjectDumper.Write(orders);
        }

16、public void Linq16() {
            List<Customer> customers = GetCustomerList();

            var orders =
                from c in customers
                from o in c.Orders
                where o.OrderDate >= new DateTime(1998, 1, 1)
                select new {c.CustomerID, o.OrderID, o.OrderDate};
       
            ObjectDumper.Write(orders);
        }

17、public void Linq17() {
            List<Customer> customers = GetCustomerList();

            var orders =
                from c in customers
                from o in c.Orders
                where o.Total >= 2000.0M
                select new {c.CustomerID, o.OrderID, o.Total};

            ObjectDumper.Write(orders);
        }

18、public void Linq18() {
            List<Customer> customers = GetCustomerList();

            DateTime cutoffDate = new DateTime(1997, 1, 1);

            var orders =
                from c in customers
                where c.Region == "WA"
                from o in c.Orders
                where o.OrderDate >= cutoffDate
                select new {c.CustomerID, o.OrderID};
       
            ObjectDumper.Write(orders);
        }

19、public void Linq19() {
            List<Customer> customers = GetCustomerList();

            var customerOrders =
                customers.SelectMany(
                    (cust, custIndex) =>
                    cust.Orders.Select(o => "Customer #" + (custIndex + 1) +
                                            " has an order with OrderID " + o.OrderID) );

            ObjectDumper.Write(customerOrders);
        }

20、public void Linq20() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
           
            var first3Numbers = numbers.Take(3);
           
            Console.WriteLine("First 3 numbers:");
            foreach (var n in first3Numbers) {
                Console.WriteLine(n);
            }
        }

21、public void Linq21() {
            List<Customer> customers = GetCustomerList();

            var first3WAOrders = (
                from c in customers
                from o in c.Orders
                where c.Region == "WA"
                select new {c.CustomerID, o.OrderID, o.OrderDate} )
                .Take(3);
           
            Console.WriteLine("First 3 orders in WA:");
            foreach (var order in first3WAOrders) {
                ObjectDumper.Write(order);
            }
        }

22、public void Linq22() {
            int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
           
            var allButFirst4Numbers = numbers.Skip(4);
           
            Console.WriteLine("All but first 4 numbers:");
            foreach (var n in allButFirst4Numbers) {
                Console.WriteLine(n);
            }
        }

23、public void Linq23() {
            List<Customer> customers = GetCustomerList();

            var waOrders =
                from c in customers
                from o in c.Orders
                where c.Region == "WA"
                select new {c.CustomerID, o.OrderID, o.OrderDate};
       
            var allButFirst2Orders = waOrders.Skip(2);
           
            Console.WriteLine("All but first 2 orders in WA:");
            foreach (var order in allButFirst2Orders) {
                ObjectDumper.Write(order);
            }
        }