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==Conditional Count==

<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, 2, 0 };
int oddNumbers = numbers.Count(n => n % 2 == 1);
Console.WriteLine("There are {0} odd numbers in the list.", oddNumbers);
}
}</source>

==Count with string operator==

<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"};
int count = presidents.Count(s => s.StartsWith("H"));
Console.WriteLine(count);
}
}</source>

==Count with string value==

<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"};
int count = presidents.Count();
Console.WriteLine(count);
}
}</source>

==Nested Count==

<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 orderCounts =
from c in customers
select new { c.CustomerId, OrderCount = c.Orders.Count() };
Console.Write(orderCounts);
}
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>

==Numeric Aggregates: count==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
class Program
{
static void Main(string[] args)
{
Random generator = new Random(0);
int[] numbers = new int[1000];
for (int i = 0; i < 1000; i++)
{
numbers[i] = generator.Next();
}
var queryResults = from n in numbers where n > 100 select n;
Console.WriteLine("Count of Numbers > 100");
Console.WriteLine(queryResults.Count());
}
}</source>

==The aggregation operators return a scalar value==

<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 };
int count = numbers.Count();
int min = numbers.Min();
}
}</source>

==Use Aggregate Operators: Count==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
int[] factorsOf300 = { 2, 2, 3, 5, 5 };
int uniqueFactors = factorsOf300.Distinct().Count();
Console.WriteLine("There are {0} unique factors of 300.", uniqueFactors);
}
}</source>

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в 15:31, 26 мая 2010

Admin: 1 версия