Basics C# with Example

LINQ is largely beneficial for querying collections (or arrays). 
For example, given the following sample data: 
var classroom = new Classroom 
{ 
new Student { Name = "Alice", Grade = 97, HasSnack = true }, 
new Student { Name = "Bob", Grade = 82, HasSnack = false }, 
new Student { Name = "Jimmy", Grade = 71, HasSnack = true }, 
new Student { Name = "Greg", Grade = 90, HasSnack = false }, 
new Student { Name = "Joe", Grade = 59, HasSnack = false } 
} 
We can "query" on this data using LINQ syntax. For example, to retrieve all students who have a snack today: 
var studentsWithSnacks = from s in classroom.Students 
where s.HasSnack 
select s; 
Or, to retrieve students with a grade of 90 or above, and only return their names, not the full Student object: 
var topStudentNames = from s in classroom.Students 
where s.Grade >= 90 
select s.Name; 
The LINQ feature is comprised of two syntaxes that perform the same functions, have nearly identical performance, 
but are written very differently. The syntax in the example above is called query syntax. The following example, 
however, illustrates method syntax. The same data will be returned as in the example above, but the way the 
query is written is different. 
var topStudentNames = classroom.Students 
.Where(s => s.Grade >= 90) 
.Select(s => s.Name);