Code-Sage

C# language feature:

  • Iterators

applies to

  • collections

benefit

  • Allows a standard way to traverse of a collection of objects. Facilitate iterator pattern.

how to use

  • 1) Include using System.Collections;
  • 2) Implement IEnumerable method.
  • 3) Create a loop block which returns an iteration value. Precede the return statement in the loop with yeild keyword.

example:

    static class Iterator_Example
    {

        // 1) don't forget to include `using System.Collections;`

        // 2) Implement `IEnumerable` method.
        public static System.Collections.IEnumerable Powers(int number, int maxPower)
        {
            int counter = 0;
            int result = 1;
            while (counter++ < maxPower) // 3) create a loop block which
            {
                result = result * number;
                yield return result; // returns an iteration preceded by yield keyword
                // note that each iteration "remembers state" i.e. counter and result variables
                // also note the return statement pauses/yeilds for the next call
            }
        }
    }
    class Use_of_Iterator_Example
    {
        public void go_iterate(){
            foreach (var currentIteration in Iterator_Example.Powers(3, 4))
            {
                System.Console.WriteLine(currentIteration); // 3, 9, 27, 81
            }
        }
    }
C# articles

csharp v2 +

Anonymous methods * Co- and Contra-variance for delegates * Delegate inference * Generics * Getter and setter separate accessibility * Iterators * Method group conversions (delegates) * Nullable types * Partials * Static classes *

csharp v3 +

Anonymous types * Auto-Implemented properties * Expression trees * Extension methods * Implicitly typed local variables * Lambda expression * Object and collection initializers * Partial methods * Query expressions *

csharp v4 +

Generic co- and contravariance * Named and optional arguments *

csharp v5 +

Asynchronous methods * Caller info attributes *

csharp v6 +

A note for CSharp 6 and beyond * Allow await in catch and finally blocks * Auto property initializers * Default values for Read-only Auto-properties * Dictionary (index) initializers * Exception filters * Expression-bodied members * Import of static type members into namespace * Null propagator (null-conditional operator, succinct null checking) * String interpolation * nameof operator *

csharp v7 +

Binary literals * Deconstruction * Digit separators * Expression bodied constructors and finalizers * Expression bodied getters and setters * Generalized async return types * Local functions * Out variables * Pattern matching * Ref returns and locals * Tuples *