How to: Write LINQ Queries in C#

http://msdn.microsoft.com/ru-ru/library/bb397678.aspx

Method Syntax

List<int> numbers1 = new List<int>() { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };
List<int> numbers2 = new List<int>() { 15, 14, 11, 13, 19, 18, 16, 17, 12, 10 };
// Query #4.
double average = numbers1.Average();

// Query #5.
IEnumerable<int> concatenationQuery = numbers1.Concat(numbers2);

IEnumerable<int> largeNumbersQuery = numbers2.Where(c => c > 15);