102 words (approximately 1 min)

Let clause

Use the let clause to store the result of an expression, such as a method call, in a new range variable (identifier).

Example 1

var studentQuery = from student in students
    let totalScore = studentScores[0] + student.Scores[1] + studentScores[2] + student.Scores[3]
    select totalScore; // The new identifier can also be selected

Example 2

var studentQuery =
    from student in students
    let x = student.Scores[0] + student.Scores[1] + student.Scores[2] + student.Scores[3]
    where x > averageScore
    select new { id = student.ID, score = x }; // A new anonymous type of a sequence of Students with their score and student ID