Enumerbale 类静态方法

扩展：

 

delegate TResult  Func<in T1,in T2,out TResult>(T1 arg1, T2 arg2);

上面定义了一个委托，声明了一种方法的类型，什么类型呢？传入两个参数  arg1 和 arg2 这两个参数可以不同类型，返回一个结果，这个结果的类型还可以不同于参数的类型。至于方法中是怎么实现，并不做要求。

static void Main(string[] args) { Func<string, int, bool> f1 = FuncDemo; Console.WriteLine(f1("x",10)); } public static bool FuncDemo(string arg1, int arg2) { return string.IsNullOrEmpty(arg1 + arg2); }<span id="mce_marker" data-mce-type="bookmark"></span><span id="__caret">_</span><span id="mce_marker" data-mce-type="bookmark"></span><span id="__caret">_</span>

        static void Main(string[] args)
        {
            Func<string, int, bool> f1 = FuncDemo;
            Console.WriteLine(f1("x",10));
        }

        public static bool FuncDemo(string arg1, int arg2)
        {
            return string.IsNullOrEmpty(arg1 + arg2);
        }

 

Aggregate 聚集、聚合

三个函数重载

public static TSource Aggregate<TSource>(Func<TSource, TSource, TSource> func); public static TAccumulate Aggregate<TSource, TAccumulate>(TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> func); public static TResult Aggregate<TSource, TAccumulate, TResult>(TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> func, Func<TAccumulate, TResult> resultSelector);

public static TSource Aggregate<TSource>(Func<TSource, TSource, TSource> func);
public static TAccumulate Aggregate<TSource, TAccumulate>(TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> func);
public static TResult Aggregate<TSource, TAccumulate, TResult>(TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> func, Func<TAccumulate, TResult> resultSelector);

 

对于第一个重载，要求传入的这个函数，对我的集合数据做操作