в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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2010-05-26T12:15:54Z

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==Compact Code for looping through the List with delegate==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.ruponentModel;
class UglyButCompactCode
{
static void Main()
{
List<int> x = new List<int>();
x.Add(5);
x.Add(10);
x.Add(15);
x.Add(20);
x.Add(25);
x.ForEach(delegate(int n) { Console.WriteLine(Math.Sqrt(n)); });
}
}</source>

==Converting a list from list of string to list of int==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
public static void Main()
{
List<string> stringList1 = new List<string>(new string[] { "99", "182", "15" });
List<int> intList1 = stringList1.ConvertAll<int>(Convert.ToInt32);
}
}</source>

==Converting a list: user defined converting function==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
private static int ConvertStringToInt(string input)
{
int result;
if (!int.TryParse(input, out result))
result = -1;
return result;
}
public static void Main()
{
List<string> stringList2 = new List<string>(new string[] { "99", "182", "invalid", "15" });
List<int> intList2 = stringList2.ConvertAll<int>(ConvertStringToInt);
}
}</source>

==Implement IComparable to use List.Sort==

<source lang="csharp">using System;
using System.Collections.Generic;
public class Employee : IComparable<Employee>
{
private int empID;
public Employee(int empID)
{
this.empID = empID;
}
public override string ToString()
{
return empID.ToString();
}
public bool Equals(Employee other)
{
if (this.empID == other.empID)
{
return true;
}
else
{
return false;
}
}
public int CompareTo(Employee rhs)
{
return this.empID.rupareTo(rhs.empID);
}
}
public class Tester
{
static void Main()
{
List<Employee> empArray = new List<Employee>();
List<Int32> intArray = new List<Int32>();
for (int i = 0; i < 5; i++)
{
empArray.Add(new Employee(i));
intArray.Add(i);
}
intArray.Sort();
for (int i = 0; i < intArray.Count; i++)
{
Console.Write("{0} ", intArray[i].ToString());
}
empArray.Sort();
for (int i = 0; i < empArray.Count; i++)
{
Console.Write("{0} ", empArray[i].ToString());
}
}
}</source>

==List Convert All==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.ruponentModel;
class ListConvertAll
{
static double TakeSquareRoot(int x)
{
return Math.Sqrt(x);
}
static void Main()
{
List<int> integers = new List<int>();
integers.Add(1);
integers.Add(2);
integers.Add(3);
integers.Add(4);
Converter<int, double> converter = TakeSquareRoot;
List<double> doubles = integers.ConvertAll<double>(converter);
foreach (double d in doubles)
{
Console.WriteLine(d);
}
}
}</source>

==List Filtering With Linq==

<source lang="csharp">using System.Text;
using System.Xml.Linq;
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Linq;
using System.Collections;
public class Product
{
string name;
public string Name
{
get { return name; }
}
decimal price;
public decimal Price
{
get { return price; }
}
public Product(string name, decimal price)
{
this.name = name;
this.price = price;
}

public override string ToString()
{
return string.Format("{0}: {1}", name, price);
}
}
class ListFilteringWithLinq
{
public static List<Product> GetSampleProducts()
{
List<Product> list = new List<Product>();
list.Add(new Product("C", 9.99m));
list.Add(new Product("A", 1.99m));
list.Add(new Product("F", 2.99m));
list.Add(new Product("S", 3.99m));
return list;
}
static void Main()
{
List<Product> products = GetSampleProducts();
var filtered = from Product p in products
where p.Price > 10
select p;
foreach (Product product in filtered)
{
Console.WriteLine(product);
}
}
}</source>

==List.ForEach==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.ruponentModel;
class Primes
{
static void Main()
{
List<int> candidates = new List<int>();
for (int i=2; i <= 100; i++)
{
candidates.Add(i);
}
for (int factor=2; factor <= 10; factor++)
{
candidates.RemoveAll (delegate(int x)
{ return x>factor && x%factor==0; }
);
}
candidates.ForEach (delegate(int prime)
{ Console.WriteLine(prime); }
);
}
}</source>

==List Joining Ordering And Filtering With Linq==

<source lang="csharp">using System.Text;
using System.Xml.Linq;
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Linq;

class ProductWithSupplierID
{
public string Name { get; private set; }
public decimal Price { get; private set; }
public int SupplierID { get; private set; }
public ProductWithSupplierID(string name, decimal price)
{
Name = name;
Price = price;
}
ProductWithSupplierID()
{
}
public static List<ProductWithSupplierID> GetSampleProducts()
{
return new List<ProductWithSupplierID>
{
new ProductWithSupplierID { Name="C", Price = 9.99m, SupplierID=1 },
new ProductWithSupplierID { Name="A", Price=14.99m, SupplierID=2 },
new ProductWithSupplierID { Name="F", Price=13.99m, SupplierID=1 },
new ProductWithSupplierID { Name="S", Price=10.99m, SupplierID=3}
};
}
public override string ToString()
{
return string.Format("{0}: {1}", Name, Price);
}
}
class Supplier
{
public string Name { get; private set; }
public int SupplierID { get; private set; }
Supplier()
{
}
public static List<Supplier> GetSampleSuppliers()
{
return new List<Supplier>
{
new Supplier { Name="S", SupplierID=1 },
new Supplier { Name="C", SupplierID=2 },
new Supplier { Name="B", SupplierID=3 }
};
}
}
class ListJoiningOrderingAndFilteringWithLinq
{
static void Main()
{
List<ProductWithSupplierID> products = ProductWithSupplierID.GetSampleProducts();
List<Supplier> suppliers = Supplier.GetSampleSuppliers();
var filtered = from p in products
join s in suppliers
on p.SupplierID equals s.SupplierID
where p.Price > 10
orderby s.Name, p.Name
select new
{
SupplierName = s.Name,
ProductName = p.Name
};
foreach (var v in filtered)
{
Console.WriteLine("Supplier={0}; Product={1}",
v.SupplierName, v.ProductName);
}
}
}</source>

==List Order With Extension Method==

<source lang="csharp">using System.Text;
using System.Xml.Linq;
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Linq;
class Product
{
public string Name { get; private set; }
public decimal Price { get; private set; }
public Product(string name, decimal price)
{
Name = name;
Price = price;
}
Product()
{
}
public static List<Product> GetSampleProducts()
{
return new List<Product>
{
new Product { Name="C", Price=9.99m },
new Product { Name="A", Price=14.99m },
new Product { Name="F", Price=13.99m },
new Product { Name="S", Price=10.99m}
};
}
public override string ToString()
{
return string.Format("{0}: {1}", Name, Price);
}
}
class ListOrderWithExtensionMethod
{
static void Main()
{
List<Product> products = Product.GetSampleProducts();
foreach (Product product in products.OrderBy(p => p.Name))
{
Console.WriteLine(product);
}
}
}</source>

==List Query With Delegates==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.ruponentModel;
public class Product
{
string name;
public string Name
{
get { return name; }
}
decimal price;
public decimal Price
{
get { return price; }
}
public Product(string name, decimal price)
{
this.name = name;
this.price = price;
}
public static List<Product> GetSampleProducts()
{
List<Product> list = new List<Product>();
list.Add(new Product("C", 9.99m));
list.Add(new Product("A", 1.99m));
list.Add(new Product("F", 2.99m));
list.Add(new Product("S", 3.99m));
return list;
}
public override string ToString()
{
return string.Format("{0}: {1}", name, price);
}
}

class ListQueryWithDelegates
{
static void Main()
{
List<Product> products = Product.GetSampleProducts();
Predicate<Product> test = delegate(Product p)
{ return p.Price > 10m; };
List<Product> matches = products.FindAll(test);
Action<Product> print = delegate(Product p)
{ Console.WriteLine(p); };
matches.ForEach(print);
}
}</source>

==List Query With Delegates Compact==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.ruponentModel;
public class Product
{
string name;
public string Name
{
get { return name; }
}
decimal price;
public decimal Price
{
get { return price; }
}
public Product(string name, decimal price)
{
this.name = name;
this.price = price;
}
public static List<Product> GetSampleProducts()
{
List<Product> list = new List<Product>();
list.Add(new Product("C", 9.99m));
list.Add(new Product("A", 1.99m));
list.Add(new Product("F", 2.99m));
list.Add(new Product("S", 3.99m));
return list;
}
public override string ToString()
{
return string.Format("{0}: {1}", name, price);
}
}

class ListQueryWithDelegatesCompact
{
static void Main()
{
List<Product> products = Product.GetSampleProducts();
products.FindAll(delegate(Product p) { return p.Price > 10; })
.ForEach(delegate(Product p) { Console.WriteLine(p); });
}
}</source>

==List Query With Lambda Expression==

<source lang="csharp">using System.Text;
using System.Xml.Linq;
using System;
using System.Collections.Generic;
using System.ruponentModel;
using System.Linq;
class Product
{
public string Name { get; private set; }
public decimal Price { get; private set; }
public Product(string name, decimal price)
{
Name = name;
Price = price;
}
Product()
{
}
public static List<Product> GetSampleProducts()
{
return new List<Product>
{
new Product { Name="C", Price=9.99m },
new Product { Name="A", Price=14.99m },
new Product { Name="F", Price=13.99m },
new Product { Name="S", Price=10.99m}
};
}
public override string ToString()
{
return string.Format("{0}: {1}", Name, Price);
}
}
class ListQueryWithLambdaExpression
{
static void Main()
{
List<Product> products = Product.GetSampleProducts();
foreach (Product product in products.Where(p => p.Price > 10))
{
Console.WriteLine(product);
}
}
}</source>

==List Sort With Comparer==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Collections;
using System.ruponentModel;
public class Product
{
string name;
public string Name
{
get { return name; }
}
decimal price;
public decimal Price
{
get { return price; }
}
public Product(string name, decimal price)
{
this.name = name;
this.price = price;
}
public static List<Product> GetSampleProducts()
{
List<Product> list = new List<Product>();
list.Add(new Product("C", 9.99m));
list.Add(new Product("A", 1.99m));
list.Add(new Product("F", 2.99m));
list.Add(new Product("S", 3.99m));
return list;
}
public override string ToString()
{
return string.Format("{0}: {1}", name, price);
}
}

class ListSortWithComparer
{
class ProductNameComparer : IComparer<Product>
{
public int Compare(Product first, Product second)
{
return first.Name.rupareTo(second.Name);
}
}
static void Main()
{
List<Product> products = Product.GetSampleProducts();
products.Sort(new ProductNameComparer());
foreach (Product product in products)
{
Console.WriteLine(product);
}
}
}</source>

==List Sort With Comparison Delegate==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.ruponentModel;
public class Product
{
string name;
public string Name
{
get { return name; }
}
decimal price;
public decimal Price
{
get { return price; }
}
public Product(string name, decimal price)
{
this.name = name;
this.price = price;
}
public static List<Product> GetSampleProducts()
{
List<Product> list = new List<Product>();
list.Add(new Product("C", 9.99m));
list.Add(new Product("A", 1.99m));
list.Add(new Product("F", 2.99m));
list.Add(new Product("S", 3.99m));
return list;
}
public override string ToString()
{
return string.Format("{0}: {1}", name, price);
}
}
class ListSortWithComparisonDelegate
{
static void Main()
{
List<Product> products = Product.GetSampleProducts();
products.Sort(delegate(Product first, Product second)
{ return first.Name.rupareTo(second.Name); }
);
foreach (Product product in products)
{
Console.WriteLine(product);
}
}
}</source>

==Obtaining a read-only copy of a list==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
public static void Main()
{
List<int> intList = new List<int>(new int[] { 3, 5, 15, 1003, 25 });
ReadOnlyCollection<int> roList = intList.AsReadOnly();
}
}</source>

==Using external method to pass into Find method==

<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)
{
List<string> myList = new List<string>();
myList.Add("A");
myList.Add("B");
myList.Add("C");
myList.Add("D");
string vanilla = myList.Find(FindVanilla);
Console.WriteLine(vanilla);
}
public static bool FindVanilla(string icecream)
{
return icecream.Equals("B");
}
}</source>

==Using the Action<T> delegate==

<source lang="csharp">using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
public static void Main()
{
List<int> intList = new List<int>(new int[] { 3, 5, 15, 1003, 25 });

intList.ForEach(delegate(int x) { Console.WriteLine(x); });
}
}</source>
<pre class=codeResult>3
5
15
1003
25</pre>

==Vector extends List==

<source lang="csharp">using System;
using System.Collections.Generic;
using System.Text;
public static class VectorDelegates {
public static int Compare(Vector x, Vector y) {
if (x.R > y.R) {
return 1;
} else if (x.R < y.R) {
return -1;
}
return 0;
}
public static bool TopRightQuadrant(Vector target) {
if (target.Theta >= 0.0 && target.Theta <= 90.0) {
return true;
} else {
return false;
}
}
}
public class Vectors : List<Vector> {
public Vectors() {
}
public Vectors(IEnumerable<Vector> initialItems) {
foreach (Vector vector in initialItems) {
Add(vector);
}
}
public string Sum() {
StringBuilder sb = new StringBuilder();
Vector currentPoint = new Vector(0.0, 0.0);
sb.Append("origin");
foreach (Vector vector in this) {
sb.AppendFormat(" + {0}", vector);
currentPoint += vector;
}
sb.AppendFormat(" = {0}", currentPoint);
return sb.ToString();
}
}
public class Vector {
public double? R = null;
public double? Theta = null;
public double? ThetaRadians {
get {
return (Theta * Math.PI / 180.0);
}
}
public Vector(double? r, double? theta) {
if (r < 0) {
r = -r;
theta += 180;
}
theta = theta % 360;
R = r;
Theta = theta;
}
public static Vector operator +(Vector op1, Vector op2) {
try {
double newX = op1.R.Value * Math.Sin(op1.ThetaRadians.Value)
+ op2.R.Value * Math.Sin(op2.ThetaRadians.Value);
double newY = op1.R.Value * Math.Cos(op1.ThetaRadians.Value)
+ op2.R.Value * Math.Cos(op2.ThetaRadians.Value);
double newR = Math.Sqrt(newX * newX + newY * newY);
double newTheta = Math.Atan2(newX, newY) * 180.0 / Math.PI;
return new Vector(newR, newTheta);
} catch {
return new Vector(null, null);
}
}
public static Vector operator -(Vector op1) {
return new Vector(-op1.R, op1.Theta);
}
public static Vector operator -(Vector op1, Vector op2) {
return op1 + (-op2);
}
public override string ToString() {
string rString = R.HasValue ? R.ToString() : "null";
string thetaString = Theta.HasValue ? Theta.ToString() : "null";
return string.Format("({0}, {1})", rString, thetaString);
}
}
class Program {
static void Main(string[] args) {
Vectors route = new Vectors();
route.Add(new Vector(2.0, 90.0));
route.Add(new Vector(1.0, 180.0));
route.Add(new Vector(0.5, 45.0));
route.Add(new Vector(2.5, 315.0));
Console.WriteLine(route.Sum());
Comparison<Vector> sorter = new Comparison<Vector>(VectorDelegates.rupare);
route.Sort(sorter);
Console.WriteLine(route.Sum());
Predicate<Vector> searcher = new Predicate<Vector>(VectorDelegates.TopRightQuadrant);
Vectors topRightQuadrantRoute = new Vectors(route.FindAll(searcher));
Console.WriteLine(topRightQuadrantRoute.Sum());
}
}</source>

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