static void Main(string[] args)
{
// DataTables
// Dictionary
Dictionary <string, string> animalFood = new Dictionary <string, string>();
animalFood.Add("Dog", "Bone,Meat");
animalFood["Cat"] = "Fish";
//string food = animalFood["Wolf"];
if (animalFood.TryGetValue("Wolf", out string food))
{
}
if (animalFood.ContainsKey("Wolf"))
{
string food2 = animalFood["Wolf"];
}
// List
string animals = "Dog,Cat,Elephont";
string[] arr1 = animals.Split(',');
List <string> list1 = new List <string>(arr1);
list1.Add("Wolf");
list1.Insert(0, "Fox");
string[] arr4 = { "Bird", "Mouse" };
list1.AddRange(arr4);
list1.Remove("Dog");
// - 排序
//list1.Sort();
//list1.Sort((x, y) => x.Length < y.Length ? -1 : 1);
list1.Sort((x, y) => x.Length.CompareTo(y.Length));
string[] arr3 = list1.ToArray();
List <string> list2 = list1.FindAll(x => x.Length == 4);
list1.RemoveAll(x => x.Length == 4);
// Array
foreach (string item in arr1)
{
Console.WriteLine(item);
}
string[] arr2 =
{
"111",
"2222",
};
// Enum
int score = (int)Enum.Parse(typeof(tagScoreLevel), "Good");
Console.WriteLine("输入您的考试分数：");
if (int.TryParse(Console.ReadLine(), out int iScore))
{
tagScoreLevel level1 = tagScoreLevel.Low;
if (iScore >= (int)tagScoreLevel.Good)
{
level1 = tagScoreLevel.Good;
}
//switch (level1)
//{
// case tagScoreLevel.Low:
// break;
// case tagScoreLevel.Good:
// break;
// default:
// break;
//}
Console.WriteLine("您的表现：" + level1.ToString());
}
//Animal animal = Animal.CreateAnimal(5,"Cat");
//animal.Age = 3;
//animal.Name = "Dog";
//Animal animal = new Animal() { Age = 4, Name = "Elephont" };
//animal.SayIt();
//Animal.Jump();
/*
* Cat cat = new Cat(2,"Cat","It is a lovely Cat");
* cat.SayIt();
* cat.Run();
*
* IRun runObj = cat;
* runObj.Run();
*
*/
/*
* Animal animal1 = new Cat(2, "Cat", "It is a lovely Cat");
* if (animal1 is IMouseHunter catObj)
* {
* catObj.CatchMouse();
* catObj.job1();
* }
*
*
*
* //Cat cat1 = new Cat(2, "Cat", "It is a lovely Cat");
* //cat1.Run();
*
* IRun[] arrInfRun =
* {
* new Dog(3,"Dog","It is a brave Dog."),
* new Cat(2,"Cat","It is a lovely Cat")
* };
*
*
* foreach (var item in arrInfRun)
* {
* item.Run();
*
* if(item is Dog dog)
* {//类型转换安全的。返回true
* dog.CatchABall();
* }
*
* //Dog dog1 = item as Dog;
* //if (dog1 != null)
* //{
* // dog1.CatchABall();
* //}
* }
*/
//TestVarType();
//return;
/*
* int loop = 0;
* while (loop<10)
* {
* Console.WriteLine($"loop value is {loop}");
* loop++;
* }
*/
//Debug.WriteLine("调试输出内容");
//Console.Error.WriteLine("错误信息");
/*
* int i1 = 10, i2 = 10;
*
* int r1 = i1 / i2;
*
* Console.WriteLine($"{i1} / {i2}的计算结果是 {r1}");
*/
/*
* Car1 car1 = new Car1();
*
* car1.Say1();
*
* car1.ChangeMyTitle("Red Name");
* car1.Say1();
* Console.WriteLine("Hello 2021!");
*/
}
static void Main(string[] args)
{
// 让 Switch更加直观
tagScoreLevel level1 = tagScoreLevel.Good;
string disp = "";
/*
* switch (level1)
* {
* case tagScoreLevel.Low:
* disp = "不行啊";
* break;
* case tagScoreLevel.Good:
* disp = "挺不错";
* break;
* default:
* disp = "unknown";
* break;
* }
*/
disp = level1 switch
{
tagScoreLevel.Low => "不行啊",
tagScoreLevel.Good => "挺不错",
_ => "unknown",
};
Console.WriteLine(disp);
// 方法代替LINQ表达式
//int[] numbers = new[] { 1, 34, 67, 92,87,78,55, 100, 23, 87 };
//var r1 = numbers.Where(x => x > 50 && x < 80)
// .OrderBy(x => x)
// .Select(a => $"data is {a}, +100 = {a + 100}");
//var result =
// from a in numbers // 数据源
// where (a > 50 && a < 80) // 条件
// orderby a ascending //排序
// select $"data is {a}, +100 = {a + 100}"; //返回 可以格式化，自定义计算
//foreach (var item in r1)
//{
// Console.WriteLine(item);
//}
/*
*
* print1();
*
* print2("ddd");
*
* // Lambda 源自委托方法，匿名函数
* Console.WriteLine($"{add(2,7)}");
* Console.WriteLine($"{add2(2,1)}");
*
*
*
*
*
*
*
* var animals = new[]
* {
* new{Name="Dog",Age=3,Type1="Home"},
* new{Name="Cat",Age=1,Type1="Home"},
* new{Name="Fox",Age=1,Type1="Wild"},
* new{Name="Wolf",Age=2,Type1="Wild"},
* new{Name="Monkey",Age=5,Type1="Wild"},
* };
*
* var foods = new[]
* {
* new {Name="Dog",Food="Bone,Meat"},
* new {Name="Cat",Food="Fish"},
* new {Name="Wolf",Food="Meat"},
* new {Name="Monkey",Food="Banana,Apple"},
* };
*
* var sounds = new[]
* {
* new {Name="Dog",Sound="汪汪"},
* new {Name="Cat",Sound="喵喵"},
* new {Name="Wolf",Sound="喔喔"},
* new {Name="Monkey",Sound="hi hi"},
* };
*
* var animalFood =
* from a in animals
* join f in foods //join .. in
* on a.Name equals f.Name // on ... equals
* join s in sounds //join .. in
* on a.Name equals s.Name // on ... equals
* orderby a.Name//排序字段
* select $"{a.Name} like {f.Food}. {s.Sound}";//返回值
*
* var result =
* from a in animalFood
* select $"123 {a}";
*
* foreach (var item in result)
* {
* Console.WriteLine(item);
* }
*
*
*/
/*
*
* // 方法名来调用分组
* var r1 = animals.GroupBy(a => a.Type1);//没有LINQ查询代码直观，灵活。
* foreach (var item in r1)
* {
* Console.WriteLine($"分类：{item.Key}");
*
* foreach (var x in item)
* {
* Console.WriteLine(x);
* }
* }
*
* // 查询分组
* var result =
* from a in animals
* //where a.Age>2
* group a by a.Type1 into grp
* //where grp.Count() > 2
* orderby grp.Count() descending
* select new
* {
* Type = grp.Key,
* Count = grp.Count(),
* };
*
* foreach (var item in result)
* {
* Console.WriteLine(item);
* }
*
*
*
*
*
* foreach (var item in result)
* {
* Console.WriteLine($"分类：{item.Key}");
*
* foreach (var x in item)
* {
* Console.WriteLine(x);
* }
* }
*
* var result =
* from a in animals
* group a by a.Type1;
* foreach (var item in result)
* {
* Console.WriteLine($"分类：{item.Key}");
*
* foreach (var x in item)
* {
* Console.WriteLine(x);
* }
* }
*/
/*
*
* var result =
* from a in animals
* where a.Type1 == "Wild"
* orderby a.Age descending
* select $"{a.Name},Age {a.Age}";
*
* foreach (var item in result)
* {
* Console.WriteLine(item);
* }
*/
// Group, join
/*
*
* int[] numbers = new[] { 1, 34, 67, 92, 100, 23, 87 };
*
* // var 编译的时候会自动识别类型
* var result =
* from a in numbers // 数据源
* where (a > 50 && a<80) // 条件
* orderby a ascending //排序
* select $"data is {a}, add 100 = {a+100}"; //返回 可以格式化，自定义计算
*
* foreach (var item in result)
* {
* Console.WriteLine($"{item}");
* }
*
* Console.WriteLine($"平均值：{numbers.Take(2).Average():F2}");
*
* IEnumerable<int> result = numbers.Take(3);
* foreach (var item in result)
* {
* Console.WriteLine(item.ToString());
* }
*/
}
