Month: February 2011

prints a list of numbers that are common to two integer arrays.

Posted on by coder
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class MainClass {
    public static void Main() {
        int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };
        int[] numbersB = { 1, 3, 5, 7, 8 };

        var commonNumbers = numbersA.Intersect(numbersB);

        Console.WriteLine("Common numbers shared by both arrays:");
        foreach (var n in commonNumbers) {
            Console.WriteLine(n);
        }
    }
}

Group words by length

Posted on by coder
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using System;
using System.Linq;

class HelloWorld {
    static void Main() {
        string[] words = { "A", "ss", "w", "ccc", "a" };
        var groups =
          from word in words
          orderby word ascending
          group word by word.Length into lengthGroups
          orderby lengthGroups.Key descending
          select new { Length = lengthGroups.Key, Words = lengthGroups };

        foreach (var group in groups) {
            Console.WriteLine("Words of length " + group.Length);
            foreach (string word in group.Words)
                Console.WriteLine("  " + word);
        }
    }
}

Use group to group all employees by department

Posted on by coder
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class Tree<TreeNode> : IEnumerable<TreeNode> where TreeNode : IComparable<TreeNode> {
    public Tree(TreeNode nodeValue) {
        this.NodeData = nodeValue;
        this.LeftTree = null;
        this.RightTree = null;
    }

    public void Insert(TreeNode newItem) {
        TreeNode currentNodeValue = this.NodeData;
        if (currentNodeValue.CompareTo(newItem) > 0) {
            if (this.LeftTree == null) {
                this.LeftTree = new Tree<TreeNode>(newItem);
            } else {
                this.LeftTree.Insert(newItem);
            }
        } else {
            if (this.RightTree == null) {
                this.RightTree = new Tree<TreeNode>(newItem);
            } else {
                this.RightTree.Insert(newItem);
            }
        }
    }

    public void WalkTree() {
        if (this.LeftTree != null) {
            this.LeftTree.WalkTree();
        }

        Console.WriteLine(this.NodeData.ToString());

        if (this.RightTree != null) {
            this.RightTree.WalkTree();
        }
    }

    public TreeNode NodeData { get; set; }
    public Tree<TreeNode> LeftTree { get; set; }
    public Tree<TreeNode> RightTree { get; set; }


    IEnumerator<TreeNode> IEnumerable<TreeNode>.GetEnumerator() {
        if (this.LeftTree != null) {
            foreach (TreeNode item in this.LeftTree) {
                yield return item;
            }
        }

        yield return this.NodeData;

        if (this.RightTree != null) {
            foreach (TreeNode item in this.RightTree) {
                yield return item;
            }
        }
    }
    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() {
        throw new NotImplementedException();
    }
}

class Employee : IComparable<Employee> {
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Department { get; set; }
    public int Id { get; set; }

    public override string ToString() {
        return String.Format("Id: {0}, Name: {1} {2}, Dept: {3}", this.Id, this.FirstName, this.LastName, this.Department);
    }
    int IComparable<Employee>.CompareTo(Employee other) {
        if (other == null)
            return 1;

        if (this.Id > other.Id)
            return 1;

        if (this.Id < other.Id)
            return -1;

        return 0;
    }
}

class Program {
    static void Main() {
        Tree<Employee> empTree = new Tree<Employee>(new Employee { Id = 1, FirstName = "Janet", LastName = "Gates", Department = "IT" });
        empTree.Insert(new Employee { Id = 2, FirstName = "O", LastName = "G", Department = "Marketing" });
        empTree.Insert(new Employee { Id = 4, FirstName = "K", LastName = "H", Department = "IT" });
        empTree.Insert(new Employee { Id = 6, FirstName = "L", LastName = "H", Department = "Sales" });
        empTree.Insert(new Employee { Id = 3, FirstName = "E", LastName = "L", Department = "Sales" });
        empTree.Insert(new Employee { Id = 5, FirstName = "D", LastName = "L", Department = "Marketing" });

        var employeesByDept = from e in empTree group e by e.Department;

        foreach (var dept in employeesByDept)
        {
            Console.WriteLine("Department: {0}", dept.Key);
            foreach (var emp in dept)
            {
                Console.WriteLine("	{0} {1}", emp.FirstName, emp.LastName);
            }
        }
    }
}

Use Group By

Posted on by coder
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using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Reflection;

public class MainClass{
   public static void Main(){
            var query = from m in typeof(double).GetMethods()
                        select m.Name;
            var q = from m in typeof(double).GetMethods()
                    group m by m.Name into gb
                    select new {Name = gb.Key, Overloads = gb.Count()};
   }
}

GroupBy partitions a list of numbers by their remainder when divided by 5.

Posted on by coder
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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 numberGroups =
            from n in numbers
            group n by n % 5 into g
            select new { Remainder = g.Key, Numbers = g };

        foreach (var g in numberGroups) {
            Console.WriteLine("Numbers with a remainder of {0} when divided by 5:", g.Remainder);
            foreach (var n in g.Numbers) {
                Console.WriteLine(n);
            }
        }
    }
}

uses group by to partition a list of products by category.

Posted on by coder
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class MainClass {
public static void Main() {

List products = GetProductList();

var orderGroups =
from p in products
group p by p.Category into g
select new { Category = g.Key, Products = g };

foreach (var s in orderGroups) {
Console.Write(s.Category);
}
}
static List GetProductList() {
List empTree = new 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.CompareTo(Product other) {
if (other == null)
return 1;
if (this.Id > other.Id)
return 1;

if (this.Id < other.Id) return -1; return 0; } } [/csharp]

uses group by to partition a list of each customer's orders, first by year, and then by month.

Posted on by coder
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

public class MainClass {
public static void Main() {

List customers = GetCustomerList();

var customerOrderGroups =
from c in customers
select
new {
c.CompanyName,
YearGroups =
from o in c.Orders
group o by o.OrderDate.Year into yg
select
new {
Year = yg.Key,
MonthGroups =
from o in yg
group o by o.OrderDate.Month into mg
select new { Month = mg.Key, Orders = mg }
}
};

Console.Write(customerOrderGroups);
}
static List GetCustomerList() {
List empTree = new 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 = new 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 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.CompanyName, this.Region);
}
int IComparable.CompareTo(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 {
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.CompareTo(Product other) {
if (other == null)
return 1;
if (this.Id > other.Id)
return 1;

if (this.Id < other.Id) return -1; return 0; } } [/csharp]