C# 语法糖测试--未完待续

/// <summary>

/// string扩展方法，可以用字符串变量加.的形式直接调用，this是关键

/// </summary>

public static class StringExtention

{

    private static Regex regex = new Regex("\\d+");

    public static bool IsNumber(this string s)

    {

        if (string.IsNullOrEmpty(s)) return false;

        return regex.IsMatch(s);

    }

    public static bool IsNullOrEmpty(this string s)

    {

        if (s == null|| s == "") return true;

        return false;

    }

}

void Test()

    {

        //?可空值类型，??空合并运算符

        int? a = null;//a是可空的int类型

        int? b = 100;

        int? c = a ?? b;//a为null，返回b

        Debug.Log(c);//输出100

        string s1 = null;

        string s2 = "ByeBye";

        string s3 = s1 ?? s2;//s1为null，返回s2

        //?判空运算符

        Debug.Log(s1.Length);//报错

        Debug.Log(s1?.Length);//输出null

        Debug.Log($"s1?.Length:{s1?.Length}");//未输出{}内的值

        //集合判空运算符？[]

        List<string> petList = new List<string> { "Dog", "Cat", "Bear", "Snake" };

        Debug.Log(petList?[0]);//输出Dog

        petList = null;

        Debug.Log(petList?[0]);//输出Null，不报错；用于判断数组集合是否为空

        //扩展方法

        string s = "123";

        Debug.Log(s.IsNumber());//输出True

        Debug.Log(s.IsNullOrEmpty());//输出False

        //遍历List

        List<int> list = new List<int> { 1, 2, 3, 4 };

        list.ForEach(item => Debug.Log(item));

        //匿名类

        var user = new { Name = "Tome", Age = 18, Sex = "Male" };

        //匿名方法

        Action<string> p = delegate (string s) { Debug.Log(s); };

        p("你好啊");

    }

巴特西

C# 语法糖测试--未完待续

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