using System; using System.Collections; using System.Collections.Generic; using System.Text; using System.Linq; public class MainClass{ public static void Main(){ int[] numbers = {1, 1, 3, 3}; int[] numbers2 = {1, 2, 3, 4}; Console.Write(numbers.Union(numbers2)); } }
Author: coder
prints the unique elements of two integer arrays
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 uniqueNumbers = numbersA.Union(numbersB); Console.WriteLine("Unique numbers from both arrays:"); foreach (var n in uniqueNumbers) { Console.WriteLine(n); } } }
prints unique letters from Product and Customer names
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
public class MainClass {
public static void Main() {
List
List
var productFirstChars =
from p in products
select p.ProductName[0];
var customerFirstChars =
from c in customers
select c.CompanyName[0];
var uniqueFirstChars = productFirstChars.Union(customerFirstChars);
Console.WriteLine(“Unique first letters from Product names and Customer names:”);
foreach (var ch in uniqueFirstChars) {
Console.WriteLine(ch);
}
}
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;
}
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 });
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
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
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
if (other == null)
return 1;
if (this.Id > other.Id)
return 1;
if (this.Id < other.Id) return -1; return 0; } } [/csharp]
Union Operator
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> first = presidents.Take(5); IEnumerable<string> second = presidents.Skip(4); IEnumerable<string> concat = first.Concat<string>(second); IEnumerable<string> union = first.Union<string>(second); Console.WriteLine("The count of the array is: " + presidents.Count()); Console.WriteLine("The count of the first sequence is: " + first.Count()); Console.WriteLine("The count of the second sequence is: " + second.Count()); Console.WriteLine("The count of the concat sequence is: " + concat.Count()); Console.WriteLine("The count of the union sequence is: " + union.Count()); } }
Use ToLookup to search object property
using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class Employee { public int birthYear; public string firstName; public string lastName; public static Employee[] GetEmployees() { Employee[] actors = new Employee[] { new Employee { birthYear = 1964, firstName = "K", lastName = "R" }, new Employee { birthYear = 1968, firstName = "O", lastName = "W" }, new Employee { birthYear = 1960, firstName = "J", lastName = "S" }, new Employee { birthYear = 1964, firstName = "S", lastName = "B" }, }; return (actors); } } public class MainClass { public static void Main() { ILookup<int, Employee> lookup = Employee.GetEmployees().ToLookup(k => k.birthYear); IEnumerable<Employee> actors = lookup[1964]; foreach (var actor in actors) Console.WriteLine("{0} {1}", actor.firstName, actor.lastName); } }
ToLookup Demo
using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class Employee { public string birthYear; public string firstName; public string lastName; public static Employee[] GetActors() { Employee[] actors = new Employee[] { new Employee { birthYear = "1964", firstName = "K", lastName = "R" }, new Employee { birthYear = "1968", firstName = "O", lastName = "W" }, new Employee { birthYear = "1960", firstName = "J", lastName = "S" }, new Employee { birthYear = "1964", firstName = "S",lastName = "B" }, }; return (actors); } } public class MyStringifiedNumberComparer : IEqualityComparer<string> { public bool Equals(string x, string y) { return (Int32.Parse(x) == Int32.Parse(y)); } public int GetHashCode(string obj) { return Int32.Parse(obj).ToString().GetHashCode(); } } public class MainClass { public static void Main() { ILookup<string, Employee> lookup = Employee.GetActors() .ToLookup(k => k.birthYear, new MyStringifiedNumberComparer()); IEnumerable<Employee> actors = lookup["1968"]; foreach (var actor in actors) Console.WriteLine("{0} {1}", actor.firstName, actor.lastName); } }
ToLookup with int and string
using System; using System.Linq; using System.Collections; using System.Collections.Generic; public class Employee { public int birthYear; public string firstName; public string lastName; public static Employee[] GetEmployees() { Employee[] actors = new Employee[] { new Employee { birthYear = 1964, firstName = "K", lastName = "R" }, new Employee { birthYear = 1968, firstName = "O", lastName = "W" }, new Employee { birthYear = 1960, firstName = "J", lastName = "S" }, new Employee { birthYear = 1964, firstName = "S", lastName = "B" }, }; return (actors); } } public class MainClass { public static void Main() { ILookup<int, string> lookup = Employee.GetEmployees() .ToLookup(k => k.birthYear, a => string.Format("{0} {1}", a.firstName, a.lastName)); IEnumerable<string> actors = lookup[1964]; foreach (var actor in actors) Console.WriteLine("{0}", actor); } }