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}; var numsPlusOne = from n in numbers select n + 1; Console.WriteLine("Numbers + 1:"); foreach (var i in numsPlusOne) { Console.WriteLine(i); } } }
LINQ
First OrderByDescending Prototype
using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass { public static void Main() { string[] presidents = {"ant", "arding", "arrison", "eyes", "over", "Jackson"}; IEnumerable<string> items = presidents.OrderByDescending(s => s); foreach (string item in items) Console.WriteLine(item); } }
Where with OrderBy
using System; using System.Collections.Generic; using System.Linq; public class MainClass { public static void Main() { string[] names = { "J", "P", "G", "Pa" }; IEnumerable<string> query = names.Where(n => n.Contains("a")) .OrderBy(n => n.Length) .Select(n => n.ToUpper()); } }
First OrderBy Prototype
using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class MainClass { public static void Main() { string[] presidents = {"ant", "arding", "arrison", "eyes", "over", "ackson"}; IEnumerable<string> items = presidents.OrderBy(s => s.Length); foreach (string item in items) Console.WriteLine(item); } }
uses a compound orderby to sort a list of products, first by category, and then by unit price, from highest to lowest.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
List
var sortedProducts =
from p in products
orderby p.Category, p.UnitPrice descending select p;
foreach (var s in sortedProducts) {
Console.Write(s);
}
}
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 });
return empTree;
}
}
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]
an array of string values sorted first by length, then sorted alphabetically, using a case-insentive comparison.
using System; using System.Collections.Generic; using System.Linq; using System.Text; public class CaseInsensitiveComparer : IComparer<string> { public int Compare(string x, string y) { return string.Compare(x, y, true); } } public class MainClass { public static void Main() { string[] words = { "a", "A", "b", "B", "C", "c" }; var sortedWords = words.OrderBy(a => a.Length) .ThenBy(a => a, new CaseInsensitiveComparer()); Console.Write(sortedWords); } }
uses a compound orderby to sort a list of digits first by length of their name, and then alphabetically.
using System; using System.Collections.Generic; using System.Linq; using System.Text; public class MainClass { public static void Main() { string[] digits = { "zero", "one", "two", "three"}; var sortedDigits = from d in digits orderby d.Length, d select d; Console.WriteLine("Sorted digits:"); foreach (var d in sortedDigits) { Console.WriteLine(d); } } }