LINQ C# Book


            Some query operators accept two input sequences.
Concat appends one sequence to another
Union does the same but with duplicates removed:
 
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
class Program
{
 static void Main()
 {
 int[] seq1 = { 1, 2, 3 };
 int[] seq2 = { 3, 4, 5 };
 IEnumerable concat = seq1.Concat(seq2); // { 1, 2, 3, 3, 4, 5 } 
 
 IEnumerable union = seq1.Union(seq2); // { 1, 2, 3, 4, 5 }
 }
}
 
In query syntax
 
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
class Program
{
 static void Main()
 {
 string[] names = { "C", "Java", "C#", "Javascript" };
 IEnumerable query =
 from n in names
 where n.Contains("a") // Filter elements 
 orderby n.Length // Sort elements
 select n.ToUpper(); // Translate each element (project)
 foreach (string name in query) 
 Console.WriteLine(name);
 }
}
 
The output:
JAVA
JAVASCRIPT