static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
//LINQ Query Operators
var listBooks2 =
from b in books
where b.Price < 10
orderby b.Title
select b.Title;
//LIQN Extension Methods
var listBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
var book1 = books.SingleOrDefault(b => b.Title == "ASP.NET");
var book2 = books.FirstOrDefault(b => b.Title == "C# Advanced Topics");
var book3 = books.LastOrDefault(b => b.Title == "C# Advanced Topics");
var book4 = books.Skip(2).Take(3);
var book5 = books.Count();
var book6 = books.Max(b => b.Price);
var book7 = books.Min(b => b.Price);
var book8 = books.Sum(b => b.Price);
var book9 = books.Average(b => b.Price);
System.Console.WriteLine(book9);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// Without LINQ
// var cheapBooks = new List<Book>();
// foreach (var book in books)
// {
// if (book.Price < 10)
// cheapBooks.Add(book);
// }
// LINQ query operators
var cheaperBooks = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
// LINQ extension methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var book in cheapBooks)
{
// Console.WriteLine(book.Title + " " + book.Price);
Console.WriteLine(book);
}
var bookSingle = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++");
var bookFirst = books.FirstOrDefault(b => b.Title == "C# Advanced Topics");
var count = books.Count();
var maxPrice = books.Max(b => b.Price);
Console.WriteLine(bookSingle == null);
Console.WriteLine(bookFirst.Title + " " + bookFirst.Price);
Console.WriteLine(maxPrice);
/*
* books.Where();
* books.Single();
* books.SingleOrDefault();
*
* books.First();
* books.FirstOrDefault();
*
* books.Last();
* books.LastOrDefault();
*
* books.Min();
* books.Max();
* books.Count();
* books.Sum();
* books.Average(b => b.Price);
*
* books.Skip(2).Take(3);
*/
}
public static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
//var book = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++");
//var book = books.First(b => b.Title == "C# Advanced Topics");
var book = books.FirstOrDefault(b => b.Title == "Bleh");
var bookTwo = books.Last(b => b.Title == "C# Advanced Topics");
var pagedBooks = books.Skip(2).Take(3);
var countBooks = books.Count();
var maxPrice = books.Max(b => b.Price);
var sumBooks = books.Sum(b => b.Price);
//Null because "Bleh" doesn't exist
try
{
Console.WriteLine(book.Price);
}
catch (NullReferenceException)
{
Console.WriteLine("Book is null");
}
Console.WriteLine(bookTwo.Price);
foreach (var pageBook in pagedBooks)
{
Console.WriteLine("\n" + pageBook.Title + "| " + pageBook.Price);
}
Console.WriteLine("\nTotal Books: " + countBooks);
Console.WriteLine("\nMax Price: " + maxPrice);
Console.WriteLine("\nSum Price: " + sumBooks);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// Without LINQ we had to do this
//var cheapBooks = new List<Book>();
//foreach (var book in books)
// if (book.Price < 10)
// cheapBooks.Add(book);
// With LINQ we can do this
// Linq Query Operators
//var cheaperBooks = from b in books
// where b.Price < 10
// orderby b.Title
// select b.Title;
// Linq Extension Methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title); // cheapBooks is now an emumerable of type string
foreach (var book in cheapBooks)
{
Console.WriteLine(book);
}
//Console.WriteLine(book.Title + " " + book.Price);
var singleBook = books.Single(b => b.Title == "ASP.NET MVC"); // Must have one and only one object that satisfies condition
var singleBookd = books.SingleOrDefault(b => b.Title == "ASP.NET MVC"); // returns match or default in this case null
Console.WriteLine(singleBook.Title);
var firstBook = books.First(b => b.Title == "C# Advanced Topics");
Console.WriteLine(firstBook.Title + " " + firstBook.Price); // also has FirstOrDefault
var skipBooks = books.Skip(2).Take(3);
foreach (var skipBook in skipBooks)
{
Console.WriteLine(skipBook.Title);
}
var count = books.Count();
var maxPrice = books.Max(b => b.Price);
Console.WriteLine(maxPrice); //returns float Price 12 in this case
var totalPrice = books.Sum(b => b.Price);
Console.WriteLine(totalPrice);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
//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); // title of the book
}
//LINQ Extension methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var book in cheapBooks)
{
Console.WriteLine(book); // title of the book
}
//this will throw error if no mathing condition
var singleBook = books.Single(b => b.Title == "ASP.NET MVC");
//there for
singleBook = books.SingleOrDefault(b => b.Title == "ASP.NET MVC");
if (singleBook != null)
{
Console.WriteLine(singleBook.Price);
}
var firstBook = books.First();
//or with predicate
firstBook = books.First(b => b.Price > 10);
//similary this method will throw an exeption if not found
firstBook = books.FirstOrDefault();
var paginatedBooks = books.Skip(2).Take(1);
var booksCount = books.Count();
var maxPrice = books.Max(b => b.Price);
var minPrice = books.Min(book => book.Price);
var sumOfPrices = books.Sum(b => b.Price);
}
// Language Integrated Query
// Give the ability to query object directly in C#
// Objects in memory(collections etc), Dbs, XML, Data Sets
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// Linq Extension Methods Syntax
var cheapBooks =
books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
// Linq Query Operators Syntax
var cheaperBooks = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
var singleBook = books.SingleOrDefault(b => b.Title == "ASP.NET MVC"); // the or default handles if the condition is not met
var first = books.First(b => b.Title == "C# Advanced Topics"); // also has an "OrDefault" verison
//.Last does the opposite
var pagedBooks = books.Skip(2).Take(3);
Console.WriteLine("count: " + books.Count());
var mostExpensive = books.Max(b => b.Price);
var mostCheap = books.Min(b => b.Price);
var totalCost = books.Sum(b => b.Price);
Console.WriteLine($"1.{mostExpensive} then 2.{mostCheap} then 3.{totalCost}");
foreach (var book in pagedBooks)
{
Console.WriteLine(book.Title);
}
//foreach (var book in cheapBooks)
//{
// //Console.WriteLine((book.Title + " " + book.Price));
// Console.WriteLine(book);
//}
//Console.WriteLine("Desired book: " + singleBook.Title);
Console.WriteLine(first.Title + " " + first.Price);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
//LINQ query Operators
var cheapers = from b in books //always the first
where b.Price < 15
orderby b.Title
select b.Title; //always the last
//LINQ extension methods
var cheapBooks = books
.Where(a => a.Price < 15)
.OrderBy(a => a.Title)
.Select(b => b.Title + b.Price);
books.Single(b => b.Title.Equals("Title 3")); //Single() return only and only the one object; if there isn't object like this, app thorws exception
//SingleOrDefault() will return null if there is not equilant object, no exception
books.First(c => c.Title == "Title 1"); //First() returns the fist on the collection that satisfies this condition
// FirstOrDefault() return default value instead of exception
books.Last(d => d.Title == "Title 2"); //Last() or LastOrDefault()
books.Skip(1).Take(2); //skip the first one and take following 2
var count = books.Count(); //number of items in collection
var mostexpensiveBook = books.Max(e => e.Price);
foreach (var b in cheapBooks)
{
Console.WriteLine(b);
}
Console.ReadKey();
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
//var cheapBooks = new List<Book>();
//foreach (var book in books)
//{
// if (book.Price < 10)
// cheapBooks.Add(book);
//}
// LINQ Query Operators
var cheaperBooks =
from b in books
where b.Price < 10
orderby b.Title
select b.Title;
// LINQ Extension Methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var book in cheaperBooks)
{
Console.WriteLine(book);
}
Console.WriteLine();
foreach (var book in cheapBooks)
{
Console.WriteLine(book);
}
Console.WriteLine();
var singleBook = books.Single(b => b.Title == "ASP.NET MVC");
Console.WriteLine(singleBook.Title);
Console.WriteLine();
var singleOrDefaultBook = books.SingleOrDefault(b => b.Title == "ASP.NET MVS++");
Console.WriteLine(singleOrDefaultBook == null);
Console.WriteLine();
var firstBook = books.First(b => b.Title == "C# Advanced Topics");
Console.WriteLine(firstBook.Title + " " + firstBook.Price);
Console.WriteLine();
var skipAndTakeBooks = books.Skip(2).Take(3);
foreach (var book in skipAndTakeBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
Console.WriteLine();
var count = books.Count();
Console.WriteLine(count);
Console.WriteLine();
var maxPrice = books.Max(b => b.Price);
Console.WriteLine(maxPrice);
Console.WriteLine();
var minPrice = books.Min(b => b.Price);
Console.WriteLine(minPrice);
Console.WriteLine();
var totalPrice = books.Sum(b => b.Price);
Console.WriteLine(totalPrice);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
//without linq
//var cheapBooks = new List<Book>();
//foreach (var book in books)
//{
// if (book.Price < 10)
// cheapBooks.Add(book);
//}
//with linq Extension methods:
var cheapBooks = books.Where(b => b.Price < 10).OrderBy(b => b.Title); //can chain linq!
//.Select is used for "projections" or "transformations".
//the below code transforms a list of books into a list of strings.
var cheapBooksTitleString = books.Select(b => b.Title);
//more reader-friendly layout:
var readerFriendly = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var book in cheapBooks)
{
Console.WriteLine($"{book.Title}, {book.Price}");
}
//with LINQ query Operators:
var cheaperBooks = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
//============
//other LINQ methods
var single = books.Single(b => b.Title == "Book 3"); //if it can't find, it will crash. It wants one and only one object, if you're not sure better to use...
Console.WriteLine(single.Title);
var singleOrDefault = books.SingleOrDefault(b => b.Title == "hmm doesnt exist"); //returns null if it can't find, better to avoid exception crashing
Console.WriteLine(singleOrDefault == null);
var first = books.First(); //gives first book
var firstWithPredicate = books.First(b => b.Title == "Book 4"); //gives first book with that title, i.e. the one with price as $14.
Console.WriteLine(firstWithPredicate.Price);
var firstOrDefault = books.FirstOrDefault(b => b.Title == "Book 08089"); //if nothing matches the lambda condition, it returns null without throwing exception
var last = books.Last();
var lastOrDefault = books.LastOrDefault();
var skip = books.Skip(2).Take(3); //this will skip the first 2, and take the next 3 to the new list.
Console.WriteLine($"Skip:");
foreach (var book in skip)
{
Console.WriteLine(book.Title);
}
var count = books.Count(); //will be 5
var max = books.Max(b => b.Price); //what does max mean? in this case, highest price.
Console.WriteLine(max); //this is the price itself.
var min = books.Min(b => b.Price);
Console.WriteLine(min);
var sum = books.Sum(b => b.Price); //sum based on price of books
Console.WriteLine(sum);
var averagePrice = books.Average(b => b.Price);
Console.WriteLine(averagePrice); //float!
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// Searches collection for items with specific conditions
var cheapBooks = books.Where(book => book.Price < 10);
foreach (var book in cheapBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
// Sorts items in collection
var orderedBooks = books.OrderBy(b => b.Title);
foreach (var book in orderedBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
// Selects all items in collection and projects them by type fields
var selectedBooks = books.Select(b => b.Title);
foreach (var book in selectedBooks)
{
Console.WriteLine(book);
}
// C# common convention layout for multiple inline LINQ statements
var booksLinq = books
.Where(book => book.Price < 10) // Searches collection for items with specific conditions
.OrderBy(b => b.Title) // Sorts items in collection
.Select(b => b.Title); // Selects all items in collection and projects them by type fields
// OR LINQ Query Operators
var booksLinqQuery =
from b in books
where b.Price < 10
orderby b.Title
select b.Title;
// Another useful LINQ Extension Methods
var singleBook = books.SingleOrDefault(b => b.Title == "ASP.NET MVC"); // returns single item or default value
Console.WriteLine(singleBook != null ? singleBook.Title : "There is no such book in collection");
var firstBook = books.FirstOrDefault(b => b.Title == "Entity Framework");
Console.WriteLine(firstBook.Title + " " + firstBook.Price);
var lastBook = books.LastOrDefault(b => b.Title == "Entity Framework");
Console.WriteLine(lastBook.Title + " " + lastBook.Price);
var skipBooks = books.Skip(2).Take(3);
foreach (var skipBook in skipBooks)
{
Console.WriteLine(skipBook.Title);
}
Console.WriteLine("Books count: " + books.Count());
Console.WriteLine("Books max price: " + books.Max(b => b.Price));
Console.WriteLine("Books min price: " + books.Min(b => b.Price));
Console.WriteLine("Sum of all books prices: " + books.Sum(b => b.Price));
Console.WriteLine("Average of all books prices: " + books.Average(b => b.Price));
}
static void Linq()
{
var books = new Linq.BookRepository().GetBooks();
// LINQ Query Operators
// var cheapBooks = from b in books
// where b.Price < 10
// orderby b.Title
// select b.Title;
// LINQ Extension Methods (This is a more used syntax and it is also more powerful)
// var cheapBooks = books
// .Where(b => b.Price < 10)
// .OrderBy(b => b.Title)
// .Select(b => b.Title);
// foreach (var cheapBook in cheapBooks)
// {
// Console.WriteLine($"{cheapBook.Title} - € {cheapBook.Price}");
// Console.WriteLine(cheapBook);
// }
// var book = books.Single(b => b.Title == "ASP.NET MVC");
// Console.WriteLine(book.Title);
// This is safer than Single
// var book = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++");
// if (book != null)
// {
// Console.WriteLine(book.Title);
// }
// var book = books.First(b => b.Title == "C# Advanced Topics");
// Console.WriteLine($"{book.Title} - € {book.Price}");
// This is safer than First
// var book = books.FirstOrDefault(b => b.Title == "C#++ Advanced Topics");
// if (book != null)
// {
// Console.WriteLine(book.Title);
// }
// var book = books.Last(b => b.Title == "C# Advanced Topics");
// Console.WriteLine($"{book.Title} - € {book.Price}");
// This is safer than Last
// var book = books.LastOrDefault(b => b.Title == "C#++ Advanced Topics");
// if (book != null)
// {
// Console.WriteLine(book.Title);
// }
// var pagedBooks = books.Skip(2).Take(3);
// foreach (var pagedBook in pagedBooks)
// {
// Console.WriteLine($"{pagedBook.Title} - € {pagedBook.Price}");
// }
var count = books.Count();
Console.WriteLine(count);
var maxPrice = books.Max(b => b.Price);
var minPrice = books.Min(b => b.Price);
Console.WriteLine(maxPrice);
Console.WriteLine(minPrice);
var totalPrice = books.Sum(b => b.Price);
Console.WriteLine(totalPrice);
var averagePrice = books.Average(b => b.Price);
Console.WriteLine(averagePrice);
}
static void Main(string[] args)
{
//Language Integrated Query
var books = new BookRepository().GetBooks();
//var cheaperBooks = new List<Book>();
//foreach (var book in books)
//{
// if (book.Price < 10)
// cheaperBooks.Add(book);
//}
//Linq Query Operators - bu kısım aslında arka planda Linq Extension Methods translate edilir
var cheaperBooks =
from b in books
where b.Price < 10
orderby b.Title
select b.Title;//select b;
//Linq Extension Methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var book in cheapBooks)
Console.WriteLine(book);
//Console.WriteLine(book.Title + " " + book.Price);
Console.ReadLine();
//var bookItem = books.Single(b => b.Title == "ASP.NET MVC++"); //null gelirse exception fırlatır
//var bookItem = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++");//null gelme ihtimali varsa kullanılır
//var bookItem = books.First(b => b.Title == "C# Advanced Topics");
//var bookItem = books.FirstOrDefault(b => b.Title == "C# Advanced Topics");
var bookItem = books.LastOrDefault(b => b.Title == "C# Advanced Topics");
Console.WriteLine(bookItem.Title + " " + bookItem.Price);
Console.ReadLine();
//Good for paging
var pagedBooks = books.Skip(2).Take(3);
foreach (var book in pagedBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
Console.ReadLine();
var count = books.Count();
Console.WriteLine(count);
Console.ReadLine();
var maxPrice = books.Max(b => b.Price);
Console.WriteLine(maxPrice);
var minPrice = books.Min(b => b.Price);
Console.WriteLine(minPrice);
var totalPrice = books.Sum(b => b.Price);
Console.WriteLine(totalPrice);
var averagePrice = books.Average(b => b.Price);
Console.WriteLine(averagePrice);
Console.ReadLine();
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// this is how you do it without LINQ
// var cheapBooks = new List<Book>();
// foreach (var book in books)
// {
// if (book.Price < 10)
// {
// cheapBooks.Add(book);
// }
// }
// LINQ Query Operators
// equivalent to Extension Methods below
var cheaperBooks = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
// LINQ Extension Methods: can chain methods
// Select used for projections
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var book in cheapBooks)
{
Console.WriteLine(book);
// Console.WriteLine(book.Title + " " + book.Price);
}
var singleBook = books.Single(b => b.Title == "ASP.NET MVC");
var singleOrDefaultBook = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++");
var firstBook = books.First(b => b.Title == "C# Advanced Topics");
var firstOrDefaultBook = books.FirstOrDefault(b => b.Title == "C# Advanced Topics++");
var lastBook = books.Last(b => b.Title == "C# Advanced Topics");
Console.WriteLine(singleBook.Title);
Console.WriteLine(singleOrDefaultBook == null ? "null" : singleOrDefaultBook.Title);
Console.WriteLine(firstBook.Title + " " + firstBook.Price);
Console.WriteLine(firstOrDefaultBook == null ? "null" : firstOrDefaultBook.Title);
Console.WriteLine(lastBook.Title + " " + lastBook.Price);
Console.WriteLine("Paged Books:");
var pagedBooks = books.Skip(2).Take(3);
foreach (var pagedBook in pagedBooks)
{
Console.WriteLine(pagedBook.Title);
}
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 sumPrice = books.Sum(b => b.Price);
Console.WriteLine(sumPrice);
}
static void Main(string[] args)
{
//Language Integrated Query
var books = new BookRepository().GetBooks();
//var cheaperBooks = new List<Book>();
//foreach (var book in books)
//{
// if (book.Price < 10)
// cheaperBooks.Add(book);
//}
//Linq Query Operators - bu kısım aslında arka planda Linq Extension Methods translate edilir
var cheaperBooks =
from b in books
where b.Price < 10
orderby b.Title
select b.Title;//select b;
//Linq Extension Methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var book in cheapBooks)
{
Console.WriteLine(book);
}
//Console.WriteLine(book.Title + " " + book.Price);
Console.ReadLine();
//var bookItem = books.Single(b => b.Title == "ASP.NET MVC++"); //null gelirse exception fırlatır
//var bookItem = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++");//null gelme ihtimali varsa kullanılır
//var bookItem = books.First(b => b.Title == "C# Advanced Topics");
//var bookItem = books.FirstOrDefault(b => b.Title == "C# Advanced Topics");
var bookItem = books.LastOrDefault(b => b.Title == "C# Advanced Topics");
Console.WriteLine(bookItem.Title + " " + bookItem.Price);
Console.ReadLine();
//Good for paging
var pagedBooks = books.Skip(2).Take(3);
foreach (var book in pagedBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
Console.ReadLine();
var count = books.Count();
Console.WriteLine(count);
Console.ReadLine();
var maxPrice = books.Max(b => b.Price);
Console.WriteLine(maxPrice);
var minPrice = books.Min(b => b.Price);
Console.WriteLine(minPrice);
var totalPrice = books.Sum(b => b.Price);
Console.WriteLine(totalPrice);
var averagePrice = books.Average(b => b.Price);
Console.WriteLine(averagePrice);
Console.ReadLine();
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
Console.WriteLine("number of books:");
var count = books.Count();
Console.WriteLine(count);
Console.WriteLine("name of books:");
foreach (var b in books)
{
Console.WriteLine("Title: " + b);
}
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
Console.WriteLine("Cheapbooks:");
foreach (var b in cheapBooks)
{
Console.WriteLine("Title: " + b);
}
Console.WriteLine("favourite book:");
var book = books.Single(b => b.Title == "Solid Mechanics");
Console.WriteLine(book.Title);
Console.WriteLine("first book in collection:");
var firstBook = books.First();
Console.WriteLine("Title: " + firstBook.Title + ". Price: " + firstBook.Price);
Console.WriteLine("last book in collection:");
var lastBook = books.Last();
Console.WriteLine("Title: " + lastBook.Title + ". Price: " + lastBook.Price);
Console.WriteLine("books after skipping first three:");
var remainingBooks = books.Skip(2).Take(2);
foreach (var b in remainingBooks)
{
Console.WriteLine(b.Title);
}
Console.WriteLine("max price: ");
var maxPrice = books.Max(b => b.Price);
Console.WriteLine(maxPrice);
Console.WriteLine("min price: ");
var minPrice = books.Min(b => b.Price);
Console.WriteLine(minPrice);
Console.WriteLine("total price: ");
var totalPrice = books.Sum(b => b.Price);
Console.WriteLine(totalPrice);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// LINQ Query Operators
// var cheaperBooks =
// from b in books
// where b.Price < 10
// orderby b.Title
// select b.Title;
books.Single(b => b.Title == "ASP.NET MVC"); // one object
books.SingleOrDefault(b => b.Title == "ASP.NET MVC++"); //no books match this condition, function returns null
Console.WriteLine(books == null);
var book = books.First(b => b.Title == "C# Advanced Topics"); // First which match
books.FirstOrDefault(b => b.Title == "C# Advanced Topics"); // null if no books match
books.Last(b => b.Title == "C# Advanced Topics");
books.LastOrDefault(b => b.Title == "C# Advanced Topics"); // null if no books match
var pagedBooks = books.Skip(2).Take(3); // skip 2 object and take 3
foreach (var pagedBook in pagedBooks)
{
Console.WriteLine(pagedBook.Title);
}
var countOfBooks = books.Count();
var maxPrice = books.Max(b => b.Price);
var minPrice = books.Min(b => b.Price);
var totalPrices = books.Sum(b => b.Price);
// books.Where() <- to filter and retun a list of books to match to a given condition
// books.Single() <- to filter and return a one book
// books.SingleOrDefault() <- if don't find book return null
// books.First()
// books.FirstOrDefault()
// books.Last()
// books.LastOrDefault()
// books.Min()
// books.Max()
// books.Count()
// books.Sum()
// books.Average(b => b.Price)
// books.Skip(5).Take(3)
// LINQ Extension Methods
// var cheapBooks = books
// .Where(b => b.Price < 10)
// .OrderBy(b => b.Title)
// .Select(b => b.Title);
// foreach (var book in cheapBooks)
// {
// Console.WriteLine(book);
// }
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
var cheapBooks = new List <Book>();
foreach (var book in books)
{
if (book.Price < 10)
{
cheapBooks.Add(book);
}
}
// ŞİMDİ AYNI FİLTRELEMEYİ LINQ İLE YAPALIM
// LINQ Extension Methods
var cheapBooks1 = books.Where(b => b.Price < 10); // Lambda Expression ve where sorgusu
// orderby kullanalım
var cheapBooks2 = books.OrderBy(b => b.Title);
// ucuca ekleyip, hem fiyata göre filtreleyip, hem Title a gore sıralayalım
var cheapBooks3 = books.Where(b => b.Price < 10).OrderBy(b => b.Title);
// ucuca ekleyip, hem fiyata göre filtreleyip, hem Title a gore sıralayalım. Select ekleyelim.
// select projection veya transformation için kullanılıyormuş
// sadece Title listesi oluştu yani string generic listesi
var cheapBooks4 = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
// (Yukarıdaki şekildeki gibi nokta, altsatırda devam etmeye, LINQ Extension Methods diyoruz.)
// Single ile sadece tek birşey seçebiliriz. Fakat dikkat et, eğer o filtren bulunamazsa, app hata verir önlem de almamışsan
var cheapBooks6 = books.Single(b => b.Title == "ASP.NET MVC");
// O objectin olmaması riski de varsa, SingleOrDefault kullanırız. Alttaki örnekte default olarak null gelir bulunamazsa...
var cheapBooks7 = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++"); // ++ eklediigimiz için bulunamıycak.
// First, aynısından sadece ilkini bulur - bulamazsa hata verir
var cheapBooks8 = books.First(b => b.Title == "C# Advanced Topics");
// FirstOrDefault, ilki, ama hiç bulamazsa default olarak bu örnekte null
var cheapBooks9 = books.FirstOrDefault(b => b.Title == "C# Advanced Topics");
// Last, aynısından sadece sonuncuyu bulur - bulamazsa hata verir
var cheapBooks10 = books.Last(b => b.Title == "C# Advanced Topics");
// LastOrDefault, sonuncusu, ama hiç bulamazsa default olarak bu örnekte null
var cheapBooks11 = books.LastOrDefault(b => b.Title == "C# Advanced Topics");
// Skip() ve Take() - ilk 2 tanesini atla, sonra 3 tanesini al
var cheapBooks12 = books.Skip(2).Take(3);
// SQL deki gibi Aggregate Func da var. mesela Count()
var bookCount = books.Count();
// SQL deki Max() - tabi price a göre max olmasını biz söylüycez - float type a return ediyor, çünkü class Books ta, Price type float
var highestPrice = books.Max(b => b.Price); // type: float
// Min()
var minPrice = books.Min(b => b.Price); // type: float
// Sum() - tüm kitapların fiyatı toplamı
var totalPrice = books.Sum(b => b.Price); // type: float
// Average() - tüm kitapların ortalama fiyatı
var avgPrice = books.Average(b => b.Price); // type: float
foreach (var book in cheapBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
foreach (var book in cheapBooks4)
{
Console.WriteLine(book);
}
foreach (var book in cheapBooks12)
{
Console.WriteLine(book.Title + " " + book.Price);
}
// LINQ Query Methods
var cheapBooks5 = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// 1. Display the list of books that are cheaper than 10$
// Without LINQ
//var cheapBooks = new List<Book>();
//foreach(var book in books)
//{
// if(book.Price < 10)
// {
// cheapBooks.Add(book);
// }
//}
// With LINQ
var cheapBooks = books
.Where(b => b.Price < 10) // We use Where to filter collections
.OrderBy(b => b.Title) // We use OrderBy and OrderByDescending to sort collections
.Select(b => b); // We use Select for custom projections or transformations
foreach (var cheapBook in cheapBooks)
{
Console.WriteLine($"{cheapBook.Title}: {cheapBook.Price}");
}
// 2. Display only one book with specific title
var aspnetBook = books.Single(b => b.Title == "ASP.NET MVC"); // We use Single / SingleOrDefault to take only one element from the collection
Console.WriteLine($"Title of book is {aspnetBook.Title} with price of {aspnetBook.Price}$");
// 3. Give me the first book which title is "C# Advanced Topics"
var firstInstanceOfCSharpAdvancedTopics = books.First(b => b.Title == "C# Advanced Topics"); // We use First / FirstOrDefault to take the first element of a collection returned that satisfied a specific predicate
Console.WriteLine($"Title of book is {firstInstanceOfCSharpAdvancedTopics.Title} with price of {firstInstanceOfCSharpAdvancedTopics.Price}$");
// 4. Skip the first two elements and take the next 3
var pagedBooks = books
.Skip(2)
.Take(3); // We use Skip and Take mainly for paging data
foreach (var pagedBook in pagedBooks)
{
Console.WriteLine($"{pagedBook.Title}: {pagedBook.Price}");
}
// 5. Count the number of elements in a collection
var noOfBooks = books.Count();
Console.WriteLine($"Total number of books in collection: {noOfBooks}");
// 6. Return the book with the maximum price
var maxPriceBook = books.Max(b => b.Price);
Console.WriteLine($"Maximum price of book is {maxPriceBook}$");
// 7. Return total sum of prices of books in the collection
var totalSumOfBookPrices = books.Sum(b => b.Price);
Console.WriteLine($"Total sum of prices of books is: {totalSumOfBookPrices}$");
// 8. Group books by title
var groups = books
.GroupBy(b => b.Title)
.Select(g => new
{
Title = g.Key,
Books = g
});
foreach (var group in groups)
{
Console.WriteLine($"Title: {group.Title}");
foreach (var book in group.Books)
{
Console.WriteLine($"\t Book Price: {book.Price}");
}
}
Console.ReadLine();
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
/*var cheapBooks = new List<Book>();
* foreach (var book in books)
* {
* if(book.Price <10)
* {
* cheapBooks.Add(book);
* }
* }*/
//LINQ Query Operators Syntax for more clean
var cheaperBooks = from b in books
where b.Price < 10
orderby b.Title
select b;
var cheaperBookTitles = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
//LINQ Extension Methods Syntax for more in depth
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title);
var cheapBookTitles = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
//books.OrderBy(b => b.Title);
foreach (var book in cheapBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
Console.WriteLine();
foreach (var book in cheapBookTitles)
{
Console.WriteLine(book);
}
Console.WriteLine();
var bookOne = books.Single(b => b.Title == "ASP.NET MVC");
Console.WriteLine(bookOne.Title + " " + bookOne.Price);
Console.WriteLine();
var bookTwo = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++");
if (bookTwo == null)
{
Console.WriteLine("null");
}
else
{
Console.WriteLine(bookTwo.Title + " " + bookTwo.Price);
}
Console.WriteLine();
var bookThree = bookTwo == null?("null"): (bookTwo.Title + " " + bookTwo.Price);
Console.WriteLine(bookThree);
Console.WriteLine();
var bookFour = books.FirstOrDefault(b => b.Title == "C# Advanced Topics");
var bookFive = bookFour == null ? ("null") : (bookFour.Title + " " + bookFour.Price);
Console.WriteLine(bookFive);
Console.WriteLine();
var bookSix = books.LastOrDefault(b => b.Title == "C# Advanced Topics");
var bookSeven = bookSix == null ? ("null") : (bookSix.Title + " " + bookSix.Price);
Console.WriteLine(bookSeven);
Console.WriteLine();
var pagedBooks = books.Skip(2).Take(3);
foreach (var book in pagedBooks)
{
Console.WriteLine(book.Title + " " + book.Price);
}
Console.WriteLine();
var count = books.Count();
Console.WriteLine(count + " books");
Console.WriteLine();
var max = books.Max(b => b.Price);
Console.WriteLine("$" + max);
Console.WriteLine();
var min = books.Min(b => b.Price);
Console.WriteLine("$" + min);
Console.WriteLine();
var sum = books.Sum(b => b.Price);
Console.WriteLine("$" + sum);
Console.WriteLine();
var avg = books.Average(b => b.Price);
Console.WriteLine("$" + avg);
//Func<int, int, int> add = (a, b) => a + b;
//Console.WriteLine(add(2, 3));
}