oap_labs

Основы LINQ

string[] teams = {"Desolator", "Daedalus", "Butterfly", "Silver Edge", "Power Treads", "Satanic"};

var selectedTeams = new List<string>();

foreach(string s in teams)
{
    if (s.ToUpper().StartsWith("D"))
        selectedTeams.Add(s);
}
    
selectedTeams.Sort();
 
foreach (string s in selectedTeams)
    Console.WriteLine(s);

Вывод:

Daedalus
Desolator

Process finished with exit code 0.

Вторая штучка

string[] teams = {"Desolator", "Daedalus", "Butterfly", "Silver Edge", "Power Treads", "Satanic"};
 
var selectedTeams = from t in teams // определяем каждый объект из teams как t
    where t.ToUpper().StartsWith("S") //фильтрация по критерию
    orderby t  // упорядочиваем по возрастанию
    select t; // выбираем объект
 
foreach (string s in selectedTeams)
    Console.WriteLine(s);

Вывод:

Satanic
Silver Edge

Process finished with exit code 0.

Третья штучка

string[] teams = {"Desolator", "Daedalus", "Butterfly", "Silver Edge", "Power Treads", "Satanic"};
 
var selectedTeams = teams
    .Where(t=>t.ToUpper().StartsWith("B"))
    .OrderBy(t => t);
 
foreach (string s in selectedTeams)
    Console.WriteLine(s);

Вывод:

Butterfly

Process finished with exit code 0.

Четвертая штучка

using System;
List<User> users = new List<User>
{
    new User {
        Name="Invoker", 
        Age=23, 
        Languages = new List<string> {
            "английский", "немецкий" }},
    new User {
        Name="Pudge", 
        Age=27, 
        Languages = new List<string> {
            "английский", "французский" }},
    new User {
        Name="Crystal maiden", 
        Age=29, 
        Languages = new List<string> {
            "английский", "испанский" }},
    new User {
        Name="Shadow Fiend", 
        Age=24, 
        Languages = new List<string> {
            "испанский", "немецкий" }}
};
 
var selectedUsers = users.Where(u => u.Age > 25);

foreach (User user in selectedUsers)
    Console.WriteLine($"{user.Name} - {user.Age}");

public class User
{
    public string Name { get; set; }
    public int Age { get; set; }
    public List<string> Languages { get; set; }
}

Вывод:

Pudge - 27
Crystal maiden - 29

Пятая штучка

List<User> users = new List<User>()
{
    new User { Name = "Timbersaw", Age = 33 },
    new User { Name = "Invoker", Age = 30 },
    new User { Name = "Timbersaw", Age = 21 },
    new User { Name = "Spectre", Age = 43 }
};

var result = users
    .OrderBy(u => u.Name)
    .ThenBy(u => u.Age);

foreach (User u in result)
    Console.WriteLine($"{u.Name} - {u.Age}");

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

Вывод:

Spectre - 43
Timbersaw - 21
Timbersaw - 33