LINQ

LINQ

 

Case 1

using System;
using System.Linq;

namespace LinqSample
{
    class Program
    {
        static void Main(string[] args)
        {
            var sample = "I enjoy writing uber-software in C#";

            var result = from c in sample
                         select c;

            foreach (var item in result)
            {
                Console.Write(item);
            }
            Console.WriteLine();

            Console.ReadKey();
        }
    }
}

 

 

Case 2 - where, orderby

using System;
using System.Linq;

namespace LinqSample
{
    class Program
    {
        static void Main(string[] args)
        {
            var sample = "I enjoy writing uber-software in C#";

            var result = from c in sample.ToLower()
                         where c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u'
                         orderby c ascending
                         select c;

            foreach (var item in result)
            {
                Console.Write(item);
            }
            Console.WriteLine();

            Console.ReadKey();
        }
    }
}

 

 

Case 3 - group

using System;
using System.Linq;

namespace LinqSample
{
    class Program
    {
        static void Main(string[] args)
        {
            var sample = "I enjoy writing uber-software in C#";

            var result = from c in sample.ToLower()
                         where c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u'
                         orderby c
                         group c by c;

            foreach (var item in result)
            {
                Console.WriteLine($"{item.Key} - {item.Count()}");
            }

            Console.ReadKey();
        }
    }
}

 

 

Case 4 - Class

using System;
using System.Collections.Generic;
using System.Linq;

namespace LinqSample
{
    class Program
    {
        static void Main(string[] args)
        {
            var people = new List<Person>
            {
                new Person{FirstName = "John", LastName = "Doe", Age = 25},
                new Person{FirstName = "Jane", LastName = "Doe", Age = 26},
                new Person{FirstName = "John", LastName = "Williams", Age = 40},
                new Person{FirstName = "Samantha", LastName = "Williams", Age = 34},
                new Person{FirstName = "Bob", LastName = "Walters", Age = 12},
            };

            var result = from p in people
                         where p.Age < 30 && p.LastName == "Doe"
                         orderby p.LastName
                         select p;

            foreach (var item in result)
            {
                Console.WriteLine($"{item.LastName}, {item.FirstName} : {item.Age}");
            }

            Console.ReadKey();
        }
    }

    public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Age { get; set; }
    }
}

 

 

 

Case 5 - Class, group

using System;
using System.Collections.Generic;
using System.Linq;

namespace LinqSample
{
    class Program
    {
        static void Main(string[] args)
        {
            var people = new List<Person>
            {
                new Person{FirstName = "John", LastName = "Doe", Age = 25},
                new Person{FirstName = "Jane", LastName = "Doe", Age = 26},
                new Person{FirstName = "John", LastName = "Williams", Age = 40},
                new Person{FirstName = "Samantha", LastName = "Williams", Age = 34},
                new Person{FirstName = "Bob", LastName = "Walters", Age = 12},
            };

            var result = from p in people
                         orderby p.LastName descending
                         group p by p.LastName;

            foreach (var item in result)
            {
                Console.WriteLine($"{item.Key}({item.Count()})");
                foreach (var p in item)
                {
                    Console.WriteLine($"  {p.LastName}, {p.FirstName} : {p.Age}");
                }
            }

            Console.ReadKey();
        }
    }

    public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Age { get; set; }
    }
}

 

 

 

 

 

 

 

https://www.youtube.com/watch?v=Z6YWWRUcJis