Linq extensions examplified

2019-01-06 14:15:40 +01:00
parent 786b398e26
commit ba2e475f5b
7 changed files with 222 additions and 0 deletions
--- a/Linq_examples/Program.cs
+++ b/Linq_examples/Program.cs
@ -0,0 +1,92 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Linq_examples
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            var books = new BookRepository().GetBooks();
+
+            //Books with price less than 10, method 1
+            var cheapBooks = new List<Book>();
+            foreach (var book in books)
+            {
+                if (book.Price < 10)
+                    cheapBooks.Add(book);
+            }
+            foreach (var book in cheapBooks)
+                Console.WriteLine(book.Title + " " + book.Price);
+            //--------------------------------------------------------
+
+            //Books with price less than 10, method 2
+            var cheapBooks2 = books.Where(b => b.Price < 10);
+            foreach (var book in cheapBooks2)
+                Console.WriteLine(book.Title + " " + book.Price);
+
+            var cheapBooks3 = books.Where(b => b.Price < 10).OrderBy(b => b.Title);
+            foreach (var book in cheapBooks3)
+                Console.WriteLine(book.Title + " " + book.Price);
+
+            //LINQ Query Operators
+            var cheaperBooks = 
+                from b in books
+                where b.Price < 10
+                orderby b.Title
+                select b.Title;
+
+            foreach (var book in cheaperBooks)
+                Console.WriteLine(book);
+            //--------------------------------------------------------
+
+            //LINQ Extension Methods
+            var cheapBooks4 = books
+                .Where(b => b.Price < 10)
+                .OrderBy(b => b
+                .Title).Select(b => b.Title);
+
+            foreach (var book in cheapBooks4)
+                Console.WriteLine(book);
+
+            //--------------------------------------------------------
+
+            var sngbook = books.Single(b => b.Title == "ASP.Net MVC");
+            Console.WriteLine(sngbook.Title);
+
+            var sngnbook = books.SingleOrDefault(b => b.Title == "ASP.Net MVC++");
+            Console.WriteLine(sngnbook==null);
+
+            var fbook = books.First(b => b.Title == "C# Advanced topics");
+            Console.WriteLine(fbook.Title+" "+fbook.Price);
+
+            var fdbook = books.FirstOrDefault(b => b.Title == "C# Advanced topicsx");
+            Console.WriteLine(fdbook==null);
+
+            var lbook = books.Last(b => b.Title == "C# Advanced topics");
+            Console.WriteLine(lbook.Title + " " + lbook.Price);
+
+            var ldbook = books.LastOrDefault(b => b.Title == "C# Advanced topicsx");
+            Console.WriteLine(ldbook == null);
+
+            var skiptakebooks = books.Skip(2).Take(3);
+            foreach (var book in skiptakebooks)
+                Console.WriteLine(book.Title + " " + book.Price);
+
+            var count = books.Count();
+            Console.WriteLine(count);
+
+            var maxPrice = books.Max(b => b.Price);
+            Console.WriteLine(maxPrice);
+
+            var minPrice = books.Min(b => b.Price);
+            Console.WriteLine(minPrice);
+
+            var priceSum = books.Sum(b => b.Price);
+            Console.WriteLine(priceSum);
+        }
+    }
+}