KW的資訊小站

1. 建立物件之後，把物件置入List內使用。
2. 使用Where() Max() Min()進行查詢。
3. 使用 Take 拿取n個。
4. 使用 foreach 列出資料。

var Users = new List<User>
{
    new User{ Id = 1, Name = "Atsai", Age = 25},
    new User{ Id = 2, Name = "Biran", Age = 36},
    new User{ Id = 3, Name = "Gray", Age = 32},
    new User{ Id = 4, Name = "Vitra", Age = 33},
    new User{ Id = 5, Name = "Fito", Age = 22},
    new User{ Id = 6, Name = "Lido", Age = 34}
};

var User_oldest = Users.Where(x => x.Age == Users.Max(x => x.Age) );
var User_youngest = Users.Min(x => x.Age);
var User_3User = Users.Take(3);

Console.WriteLine("User_3User:");
foreach (User u in User_3User)
{
    Console.WriteLine($"Id:{u.Id} , Name:{u.Name} , Age:{u.Age} ");
}
Console.WriteLine("Users:");
foreach (User u in Users)
{
    Console.WriteLine($"Id:{u.Id} , Name:{u.Name} , Age:{u.Age} ");
}
Console.WriteLine("User_oldest");
foreach (User u in User_oldest)
{
    Console.WriteLine($"Id:{u.Id} , Name:{u.Name} , Age:{u.Age} ");
}
Console.WriteLine("User_youngest:");
Console.WriteLine( User_youngest.ToString() );

public class User
{
    public int Id { get; set; }
    public string? Name { get; set; }
    public int Age { get; set; }
}

執行結果如下：

User_3User:
Id:1 , Name:Atsai , Age:25
Id:2 , Name:Biran , Age:36
Id:3 , Name:Gray , Age:32

Users:
Id:1 , Name:Atsai , Age:25
Id:2 , Name:Biran , Age:36
Id:3 , Name:Gray , Age:32
Id:4 , Name:Vitra , Age:33
Id:5 , Name:Fito , Age:22
Id:6 , Name:Lido , Age:34

User_oldest:
Id:2 , Name:Biran , Age:36

User_youngest:
22