static void Main()
{
var books = new BookRepository().GetBooks();
//LINQ Query Operators
var booksArray = books as Book[] ?? books.ToArray();
var cheaperBooks =
from b in booksArray
where b.Price < 10
orderby b.Title
select b.Title;
//LINQ Extension Methods (same as above)
var cheapBooks = booksArray
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b=>b.Title);
foreach (var b in cheapBooks)
Console.WriteLine(b);
//Console.WriteLine(book.Title + " " + book.Price);
var book = booksArray.Single(b => b.Title == "ASP.Net MVC");
var lastBook = booksArray.LastOrDefault(b => b.Price > 9);
var pagedBooks = booksArray.Skip(2).Take(3);
foreach (var pagedBook in pagedBooks)
{
Console.WriteLine(pagedBook.Title);
}
Console.WriteLine(booksArray.Sum(b=>b.Price));
}
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("-------------- all books ");
foreach (var book in books)
{
Console.WriteLine($"{book.Title}, {book.Price}");
}
// LINQ Extension Methods
var cheapBooks = books
.Where(b => b.Price < 20)
.OrderBy(b => b.Title);
var cheapBooksStrings = books
.Where(b => b.Price < 20)
.OrderBy(b => b.Title)
.Select(b => b.Title);
Console.WriteLine("-------------- get books (objects) with LINQ Extension Methods");
foreach (var book in cheapBooks)
{
Console.WriteLine($"{book.Title}, {book.Price}");
}
Console.WriteLine("-------------- get titles with LINQ Extension Methods");
foreach (var book in cheapBooksStrings)
{
Console.WriteLine(book);
}
// LINQ Query Operators
var cheapBooksWithQuery =
from b in books
where b.Price < 20
orderby b.Title
select b;
Console.WriteLine("-------------- get books (objects) with LINQ Query Operators");
foreach (var book in cheapBooksWithQuery)
{
Console.WriteLine($"{book.Title}, {book.Price}");
}
var theBook = new Book {
Title = "I dont exist", Price = 0
};
Console.WriteLine("-------------- Single");
theBook = books.SingleOrDefault(b => b.Title == "Zoo");
Console.WriteLine($"{theBook.Title}, {theBook.Price}");
Console.WriteLine("-------------- SingleOrDefault");
theBook = books.SingleOrDefault(b => b.Title == "zoo");
Console.WriteLine(theBook == null);
Console.WriteLine("-------------- First");
theBook = books.FirstOrDefault(b => b.Price == 6.99m);
Console.WriteLine($"{theBook.Title}, {theBook.Price}");
var orderedBooks = books.OrderBy(b => b.Title);
Console.WriteLine("-------------- First of ordered");
theBook = orderedBooks.FirstOrDefault(b => b.Price == 6.99m);
Console.WriteLine($"{theBook.Title}, {theBook.Price}");
Console.WriteLine("-------------- FirstOrDefault");
theBook = books.FirstOrDefault(b => b.Price == 123.99m);
Console.WriteLine(theBook == null);
Console.WriteLine("-------------- Skip, Take");
var pagedBooks = books.Skip(3).Take(4);
foreach (var book in pagedBooks)
{
Console.WriteLine($"{book.Title}, {book.Price}");
}
Console.WriteLine("-------------- Count");
Console.WriteLine($"there are {books.Count} books");
Console.WriteLine("-------------- Sum");
Console.WriteLine($"you need {books.Sum(b => b.Price)} dollars to buy all the books");
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
Console.WriteLine("number of books:");
var count = books.Count();
Console.WriteLine(count);
Console.WriteLine("name of books:");
foreach (var b in books)
{
Console.WriteLine("Title: " + b);
}
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
Console.WriteLine("Cheapbooks:");
foreach (var b in cheapBooks)
{
Console.WriteLine("Title: " + b);
}
Console.WriteLine("favourite book:");
var book = books.Single(b => b.Title == "Solid Mechanics");
Console.WriteLine(book.Title);
Console.WriteLine("first book in collection:");
var firstBook = books.First();
Console.WriteLine("Title: " + firstBook.Title + ". Price: " + firstBook.Price);
Console.WriteLine("last book in collection:");
var lastBook = books.Last();
Console.WriteLine("Title: " + lastBook.Title + ". Price: " + lastBook.Price);
Console.WriteLine("books after skipping first three:");
var remainingBooks = books.Skip(2).Take(2);
foreach (var b in remainingBooks)
{
Console.WriteLine(b.Title);
}
Console.WriteLine("max price: ");
var maxPrice = books.Max(b => b.Price);
Console.WriteLine(maxPrice);
Console.WriteLine("min price: ");
var minPrice = books.Min(b => b.Price);
Console.WriteLine(minPrice);
Console.WriteLine("total price: ");
var totalPrice = books.Sum(b => b.Price);
Console.WriteLine(totalPrice);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// 1. Display the list of books that are cheaper than 10$
// 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();
}