string[] arrays={"asd","abc","bbb","ccc"};
var results = arrays.Where(a=>a.Contains("b"));//必須加條件,返回對(duì)象

string[] arrays={"asd","abc","bbb","ccc"};
var results = arrays.Select(a => a.Contains("b"));//1、(a=>a.Value=="22")加條件查詢時(shí)，返回bool型結(jié)果

string[] arrays={"asd","abc","bbb","ccc"};
var results = arrays.Select(a => a);//1、(a=>a)沒條件，返回所有對(duì)象;

(input-parameters) => expression
//如：
 x => x * 4

(input-parameters) => { <sequence-of-statements> }
//如：
(int x) => { return x * 2; };

    public class LambdaTest
    {
        public void Test()
        {
            //表達(dá)式lambda 只有一個(gè)表達(dá)式，表示這里面只允許有一行代碼
            Func<int, int> func = x => x * 4;
            //接收表達(dá)式Lambda返回的值
            int result1 = func(5);
            //在表達(dá)式lambda中調(diào)用方法
            func = x => x * Add(3, 2);
            int result2 = func(5);
        }
        public int Add(int x,int y)
        {
            return x + y;
        }
    }

        public int FourX(int number)
        {
            return number * 4;
        }

            Action<int> action = (x) => {  Console.WriteLine(x); };
            action = (y) =>
            {
                y *= 4;
                Console.WriteLine(y);
            };

Action line = () => Console.WriteLine();

Func<double, double> cube = x => x * x * x;

Func<int, int, bool> testForEquality = (x, y) => x == y;

Func<int, string, bool> isTooLong = (int x, string s) => s.Length > x;

    public delegate void ShowDelegate(int a,string b);
    public class LambdaEvolution
    {
        public void Show(int a1,string b1)
        {
            Console.WriteLine($"show{a1}:{b1}");
        }
        public void Test()
        {
            //1 .Netframework1.0/1.1，原始方法
            ShowDelegate showDelegate = new ShowDelegate(Show);
            //2 .NetFramework2.0，匿名方法，增加delegate,去掉單獨(dú)定義方法
            showDelegate = delegate (int x,string y) { Console.WriteLine($"show{x}:{y}"); };
            //3 .NetFramework3.0，=> 引入Lambda表達(dá)式，去掉delegate
            showDelegate = (int s,string t) => { Console.WriteLine($"show{s}:{t}"); };
            //4 .NetFramework3.0后期，簡(jiǎn)化參數(shù)類型,編譯器自動(dòng)推斷數(shù)據(jù)類型
            showDelegate = (s,t) => { Console.WriteLine($"show{s}:{t}"); };
            //5 如果方法體中只有一行代碼，可以省略方法體大括號(hào)
            showDelegate = (s,t) => Console.WriteLine($"show{s}:{t}");
            //如果方法只有一個(gè)參數(shù)，可以省略參數(shù)小括號(hào)
            Action<string> action = x => Console.WriteLine($"show{x}");
            //如果方法體中只有一行代碼，且有返回值，可以省略return
            Func<int, string> func = x => x.ToString();
        }
    }