Csharp/CSharp Tutorial/LINQ/Except
Содержание
Except Prototype
<source lang="csharp">using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass {
public static void Main() { string[] presidents = {"G", "H", "a", "H", "over", "Jack"}; IEnumerable<string> processed = presidents.Take(4); IEnumerable<string> exceptions = presidents.Except(processed); foreach (string name in exceptions) Console.WriteLine(name); }
}</source>
One array expect another array
<source lang="csharp">using System; using System.Collections; using System.Collections.Generic; using System.Text; using System.Linq; public class MainClass{
public static void Main(){ int[] numbers = {1, 2, 3, 4}; int[] numbers2 = {1, 1, 3, 3}; Console.Write(numbers.Except(numbers2)); }
}</source>
Set Operators: Except
<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text;
class Customer { public string ID { get; set; } public string City { get; set; } public string Country { get; set; } public string Region { get; set; } public decimal Sales { get; set; } } class Order { public string ID { get; set; } public decimal Amount { get; set; } } class Program { static void Main(string[] args) { List<Order> orders = new List<Order> { new Order { ID="R", Amount=900 }, new Order { ID="S", Amount=1000 }, new Order { ID="T", Amount=1100 } }; List<Customer> customers = new List<Customer> { new Customer { ID="Q", City="London", Country="UK", Region="Europe", Sales=8000 }, new Customer { ID="R", City="Beijing", Country="China", Region="Asia", Sales=9000 }, new Customer { ID="T", City="Lima", Country="Peru", Region="South America", Sales=2002 } }; var customerIDs = from c in customers select c.ID; var orderIDs = from o in orders select o.ID; var ordersNoCustomers = orderIDs.Except(customerIDs); foreach (var item in ordersNoCustomers) { Console.Write("{0} ", item); } } }</source>
Use Except to print numbers that are in one integer array, but not another
<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text; public class MainClass {
public static void Main() { int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 }; int[] numbersB = { 1, 3, 5, 7, 8 }; IEnumerable<int> aOnlyNumbers = numbersA.Except(numbersB); Console.WriteLine("Numbers in first array but not second array:"); foreach (var n in aOnlyNumbers) { Console.WriteLine(n); } }
}</source>
Use Except to print the first character of product names that aren"t also the first character of customer names.
<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(); List<Customer> customers = GetCustomerList(); var productFirstChars = from p in products select p.ProductName[0]; var customerFirstChars = from c in customers select c.rupanyName[0]; var productOnlyFirstChars = productFirstChars.Except(customerFirstChars); Console.WriteLine("First letters from Product names, but not from Customer names:"); foreach (var ch in productOnlyFirstChars) { Console.WriteLine(ch); } } 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 = 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 }); 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>