http://blogs.msdn.com/b/ericlippert/archive/2007/10/17/covariance-and-contravariance-in-c-part-two-array-covariance.aspx C# implements variance in two ways. Today, the broken way. Ever since C# 1.0, arrays where the element type is a reference type a…

Covariance and Contravariance (C#) https://docs.microsoft.com/en-us/dotnet/articles/csharp/programming-guide/concepts/covariance-contravariance/ In C#, covariance and contravariance enable implicit reference conversion for array types, delegate types…

http://blogs.msdn.com/b/ericlippert/archive/2007/10/16/covariance-and-contravariance-in-c-part-one.aspx I have been wanting for a long time to do a series of articles about covariance and contravariance (which I will shorten to “variance” for the res…

http://stackoverflow.com/questions/8704332/co-variant-array-conversion-from-x-to-y-may-cause-run-time-exception What it means is this Control[] controls = new LinkLabel[10]; // compile time legal controls[0] = new TextBox(); // compile time legal, ru…

协变,逆变与不变 能在使用父类型的场景中改用子类型的被称为协变. 能在使用子类型的场景中改用父类型的被称为逆变. 不能做到以上两点的被称为不变. 以上的场景通常包括数组,继承和泛型. 协变逆变与泛型(C#,Java) 在C#中,泛型参数的类型缺省是不变的,但是我们可以在定义泛型接口或委托时通过给参数类型加上out或in来标注该参数类型是协变还是逆变. 协变意味着你能把 IEnumerable<string> 用在需要 IEnumerable<object> 的地方. 这里 IEnu…

using System; using System.Collections.Generic; using System.IO; namespace CovarientAndContraVarient { class Program { static object GetObject() { return null; } static void SetObject(object obj) { } static string GetString() { return ""; } stat…

A geometric interpretation of the covariance matrix Contents [hide] 1 Introduction 2 Eigendecomposition of a covariance matrix 3 Covariance matrix as a linear transformation 4 Conclusion Introduction In this article, we provide an intuitive, geometri…

C#是微软推出的一种基于.NET框架的.面向对象的高级编程语言.C#的发音为"C sharp",模仿音乐上的音名"C♯"(C调升),是C语言的升级的意思.其正确写法应和音名一样为"C♯"[来源请求],但大多数情况下"♯"符号被井号"#"所混用:两者差别是:"♯"的笔画是上下偏斜的,而"#"的笔画是左右偏斜.C♯由C语言和C++派生而来,继承了其强大的性能,同时又以.N…

This is a quick guide covering nearly all of Nemerle's features. It should be especially useful to anyone who is already familiar with C# or a similar language: Table of Contents Variables Operators Logical Operators Bit Operators Type Casts/Conversi…

最近在学习使用Scala语言做项目,感觉这门语言实在是太优美了!作为一个本科数学.研究生机器学习专业的混合人才(哈哈),这门语言真的是满足了普通计算机编程(告诉计算机怎么做)和函数式编程(告诉计算机做什么)的所有幻想.学了半个多月,根本停不下来!先来做个总结: 语法简洁,往往比Java少至少一半的代码量.比如: 支持自动类型判断,可以省去很多类型标志. e.g.  val x = 2 用伴生对象来生成类,省去new的麻烦.e.g. val cat = Cat("Hello Ketty"…