using System; using System.Linq; using System.Data.Linq; using System.Data.Linq.Mapping; static class HelloLinqToSql { [Table(Name = "Contacts")] class Contact { [Column(IsPrimaryKey = true)] public int ContactID { get; set; } [Column(Name = "ContactName")] public string Name { get; set; } [Column] public string City { get; set; } } static void Main() { string path = System.IO.Path.GetFullPath("northwnd.mdf"); DataContext db = new DataContext(path); var contacts = from contact in db.GetTable<Contact>() where contact.City == "Paris" select contact; foreach (var contact in contacts) Console.WriteLine("Bonjour " + contact.Name); } }
Author: coder
Use SkipWhile with index
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, 3, 5, 4}; var query = numbers.TakeWhile(( n, index) => n >= index); var query2 = numbers.SkipWhile(( n, index) => n >= index); } }
Skip the first element
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); } }
uses Skip to get all but the first 4 elements of the array.
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); } } }
Nested Skip
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
List
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
List
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
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
public string CompanyName { get; set; }
public string Region { get; set; }
public List
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.CompanyName, this.Region);
}
int IComparable
if (other == null)
return 1;
if (this.CustomerId > other.CustomerId)
return 1;
if (this.CustomerId < other.CustomerId)
return -1;
return 0;
}
}
class Product : IComparable
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
if (other == null)
return 1;
if (this.Id > other.Id)
return 1;
if (this.Id < other.Id) return -1; return 0; } } [/csharp]
Use Skip
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); } }
The Skip operator ignores the first x elements and outputs the rest
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 } } }