Csharp/CSharp Tutorial/LINQ/Skip
Содержание
Nested Skip
<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text; public class MainClass {
public static void Main() {
List<Customer> customers = GetCustomerList();
var waOrders =
from c in customers
from o in c.Orders
where c.Region == "R1"
select new { c.CustomerId, o.Id, o.OrderDate };
var allButFirst2Orders = waOrders.Skip(2);
Console.WriteLine("All but first 2 orders in R1:");
foreach (var order in allButFirst2Orders) {
Console.WriteLine(order);
}
}
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>
Skip numbes equals 50
<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Linq.Expressions; using System.Xml.Linq;
class Program
{
static void Main(string[] args)
{
int[] integers = { 1, 9, 5, 3, 7, 2, 11, 23, 50, 41, 6, 8 };
IEnumerable<int> skipWhileNumber = integers.SkipWhile(num => num.rupareTo(50) != 0);
Console.WriteLine("Skip while number equals 50");
foreach (int num in skipWhileNumber)
{
Console.WriteLine(num.ToString());
}
}
}</source>
Skip the first element
<source lang="csharp">using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass {
public static void Main() {
string[] presidents = {"A", "Art", "Buch", "Bush", "Car", "land"};
IEnumerable<string> items = presidents.Skip(1);
foreach (string item in items)
Console.WriteLine(item);
}
}</source>
Skip the first four
<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Linq.Expressions; using System.Xml.Linq;
class Program
{
static void Main(string[] args)
{
int[] integers = { 1, 6, 2, 27, 10 };
IEnumerable<int> skipFirstFourNumbers = integers.Skip(4);
Console.WriteLine("Skip first 4 numbers:");
foreach (var num in skipFirstFourNumbers)
{
Console.WriteLine(num);
}
}
}</source>
The Skip operator ignores the first x elements and outputs the rest
<source lang="csharp">using System; using System.Collections.Generic; using System.Linq; public class MainClass {
public static void Main() {
int[] numbers = { 10, 9, 8, 7, 6 };
IEnumerable<int> lastTwo = numbers.Skip(3); // { 7, 6 }
}
}</source>
Use Skip
<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, 5, 6, 7, 8, 9 };
var query = numbers.Take(5);
var query2 = numbers.Skip(5);
}
}</source>
uses Skip to get all but the first 4 elements of the 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};
var allButFirst4Numbers = numbers.Skip(4);
Console.WriteLine("All but first 4 numbers:");
foreach (var n in allButFirst4Numbers) {
Console.WriteLine(n);
}
}
}</source>
