using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
string[] digits = { "ziro", "one", "two", "three"};
var reversedIDigits = (
from d in digits
where d[1] == 'i'
select d)
.Reverse();
foreach (var d in reversedIDigits) {
Console.WriteLine(d);
}
}
}
Month: February 2011
Filtered: prints the name of each element of an integer array that is less than 5
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};
string[] digits = { “zero”, “one”, “two”, “three”};
var lowNums =
from n in numbers
where n < 5
select digits[n];
Console.WriteLine("Numbers < 5:");
foreach (var num in lowNums) {
Console.WriteLine(num);
}
}
}
[/csharp]
Use where to filer object list
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
List
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);
}
}
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]
Use && in where clause
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
List
var expensiveInStockProducts =
from p in products
where p.UnitsInStock > 0 && p.UnitPrice > 3.00M
select p;
foreach (var product in expensiveInStockProducts) {
Console.WriteLine(product.ProductName);
}
}
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]
where clause
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Reflection;
class Person {
int _id;
int _idRole;
string _lastName;
string _firstName;
public int ID {
get { return _id; }
set { _id = value; }
}
public int IDRole {
get { return _idRole; }
set { _idRole = value; }
}
public string LastName {
get { return _lastName; }
set { _lastName = value; }
}
public string FirstName {
get { return _firstName; }
set { _firstName = value; }
}
}
class Program {
static void Main(string[] args) {
List<Person> people = new List<Person> {
new Person { ID = 1, IDRole = 1, LastName = "A", FirstName = "B"},
new Person { ID = 2, IDRole = 2, LastName = "G", FirstName = "T"},
new Person { ID = 3, IDRole = 2, LastName = "G", FirstName = "M"},
new Person { ID = 4, IDRole = 3, LastName = "C", FirstName = "G"}
};
var query = people.Where((p, index) => p.IDRole == index);
}
}
Query string value by String.StartsWith
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
public static void Main() {
string[] presidents = {"Ad", "Ar", "Bu", "B", "C", "C"};
string president = presidents.Where(p => p.StartsWith("Ad")).First();
Console.WriteLine(president);
}
}
Where clause with string method and return IEnumerable object
using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass {
public static void Main() {
string[] presidents = {"AA", "A", "AAA", "B", "Ca", "C"};
IEnumerable<string> items = presidents.Where(p => p.StartsWith("A"));
foreach (string item in items)
Console.WriteLine(item);
}
}

