You will want to use the Aggregate extension method: double product = doubles.Aggregate(1.0, (prod, next) => prod * next); See MSDN for more information. It lets you specify a seed and then an expression to calculate successive values.
Extension methods are just static methods in disguise. Mocking frameworks like Moq or Rhinomocks can only create mock instances of objects, this means mocking static methods is not possible.
Since using Rails should handle this automatically I’m going to assume you’re trying to add Active Support to a non-Rails script. Read “How to Load Core Extensions”. Active Support’s methods got broken into smaller groups in Rails 3, so we don’t end up loading a lot of unneeded stuff with a simple require ‘activesupport’. Now … Read more
Use an extension method. Ex: namespace ExtensionMethods { public static class MyExtensionMethods { public static DateTime Tomorrow(this DateTime date) { return date.AddDays(1); } } } Usage: DateTime.Now.Tomorrow(); or AnyObjectOfTypeDateTime.Tomorrow();
No; an extension method never takes priority over an instance method with a suitable signature, and never participates in polymorphism (GetHashCode is a virtual method).
They have totally different semantics. AddRange modifies the list by adding the other items to it. Concat returns a new sequence containing the list and the other items, without modifying the list. Choose whichever one has the semantics you want.
JavaScript doesn’t have an exact analogue for C#’s extension methods. JavaScript and C# are quite different languages. The nearest similar thing is to modify the prototype object of all string objects: String.prototype. In general, best practice is not to modify the prototypes of built-in objects in library code meant to be combined with other code … Read more
No, this seems perfectly reasonable. There is a List<T>.AddRange() method that basically does just this, but requires your collection to be a concrete List<T>.
Another thing to keep in mind is that the string itself might be null. public static Nullable<T> ToNullable<T>(this string s) where T: struct { Nullable<T> result = new Nullable<T>(); try { if (!string.IsNullOrEmpty(s) && s.Trim().Length > 0) { TypeConverter conv = TypeDescriptor.GetConverter(typeof(T)); result = (T)conv.ConvertFrom(s); } } catch { } return result; }
In .NET 4 you can do this: String.Concat(Enumerable.Repeat(“Hello”, 4))