static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// LINQ Extension Methods
var book = books.LastOrDefault(b => b.Title == "C# Advanced Topics");
var pagedBooks = books.Skip(2).Take(1);
var count = books.Count();
var maxPrice = books.Max(b => b.Price);
var minPrice = books.Min(b => b.Price);
var totalPrices = books.Sum(b => b.Price);
Console.WriteLine(book.Title + " " + book.Price);
Console.WriteLine(book == null);
foreach (var pagedBook in pagedBooks)
{
Console.WriteLine(pagedBook.Title + " " + pagedBook.Price);
}
Console.WriteLine(count);
Console.WriteLine(maxPrice);
Console.WriteLine(minPrice);
Console.WriteLine(totalPrices);
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
// LINQ Query Operators [always start with the from and end with select]
var cheaperBooks = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
// With 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);
}
// SINGLE OBJECT
var book1 = books.SingleOrDefault(books => books.Title == "ASP.NET MVC");
Console.WriteLine(book1.Title);
// first object
var book2 = books.First(b => b.Title == "How to code");
Console.WriteLine(book2.Title + " " + book2.Price);
// last
var book3 = books.LastOrDefault(books => books.Title == "ASP.NET MVC");
Console.WriteLine(book3.Title + " " + book3.Price);
// skip
var pagedBooks = books.Skip(2).Take(3);
Console.WriteLine("\nLast 3 books: ");
foreach (var pageBook in pagedBooks)
{
Console.WriteLine(pageBook.Title);
}
// count
Console.WriteLine($"There are {books.Count()} books. ");
Console.WriteLine($"The highest priced book is P{books.Max(b => b.Price)}");
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
var cheapBooks = books.Where(b => b.Price < 10);
// LINQ Query Operator
var cheaperBooks =
from b in books
where b.Price < 10
orderby b.Title
select b.Title;
// LINQ Methods can be chained
var orderedByTitle = books
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var b in orderedByTitle)
{
Console.WriteLine(b);
}
// Other Examples
var result1 = books.Single(book => book.Title == "A");
var result2 = books.SingleOrDefault(b => b.Title == "A");
var result3 = books.FirstOrDefault(b => b.Title == "A");
var result4 = books.LastOrDefault(b => b.Title == "A");
var result5 = books.Skip(2).Take(3);
var result6 = books.Count();
var result7 = books.Max(b => b.Price);
var result8 = books.Sum(b => b.Price);
var result9 = books.Average(b => b.Price);
Console.ReadLine();
}
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;
/*---the same -----*/
//LINQ Extension Methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Title)
.Select(b => b.Title);
foreach (var bk in cheapBooks)
{
// Console.WriteLine(book.Title);
Console.WriteLine(bk);
}
/*------------------------------------------------------------------*/
var book = books.Single(b => b.Title == "ASP.NET MVC"); //throw an exception if nothing found
var book2 = books.SingleOrDefault(b => b.Title == "ASP.NET MVC++"); //return null if nothing found
Console.WriteLine(book.Title);
Console.WriteLine(book2 == null ? "null" : book2.Title);
/*-------------------------------------------------------------------*/
var book3 = books.First(); //first element of the collection
var book4 = books.First(b => b.Title == "C# Advanced Topics"); //first element of the collection
var book5 = books.FirstOrDefault(); //return null if nothing found
Console.WriteLine(book3.Title);
Console.WriteLine(book4.Price);
Console.WriteLine(book5 == null ? "null" : book5.Title);
var book6 = books.Last(); //first element of the collection
var book7 = books.Last(b => b.Title == "C# Advanced Topics"); //first element of the collection
var book8 = books.LastOrDefault(); //return null if nothing found
Console.WriteLine(book6.Title);
Console.WriteLine(book7.Price);
Console.WriteLine(book8 == null ? "null" : book8.Title);
/*-------------------------------------------------------------------*/
var books9 = books.Skip(2).Take(3); //used for paging data
//skip 2 records or two objects and take 3
foreach (var bb in books9)
{
Console.WriteLine(bb.Title);
}
/* --------------------------------------------------------------------*/
var count = books.Count();
Console.WriteLine(count);
var maxPrice = books.Max(b => b.Price);
var minPrice = books.Min(b => b.Price);
var sumPriceofAllBook = books.Sum(b => b.Price);
var average = books.Average(b => b.Price);
Console.WriteLine("maxPrice : {0} and min price : {1} and sum of all books : {2}, and finally average = {3}", maxPrice, minPrice, sumPriceofAllBook, average);
Console.ReadLine();
}
static void Main(string[] args)
{
var books = new BookRepository().GetBooks();
/*
* This can be done in one line using LINQ:
* var cheapBooks = new List<Book>();
*
* foreach(var book in books)
* {
* if(book.Price < 10)
* {
* cheapBooks.Add(book);
* }
* }
*/
// LINQ Extension methods
var cheapBooks = books
.Where(b => b.Price < 10)
.OrderBy(b => b.Price)
.Select(b => b.Title);
// LINQ Query operators
var cheaperBooks = from b in books
where b.Price < 10
orderby b.Title
select b.Title;
foreach (var book in cheapBooks)
{
//Console.WriteLine(book.Title + " " + book.Price);
Console.WriteLine(book);
}
Console.WriteLine();
foreach (var book in cheaperBooks)
{
//Console.WriteLine(book.Title + " " + book.Price);
Console.WriteLine(book);
}
Console.WriteLine();
var book1 = books.SingleOrDefault(b => b.Title == "ASP.NET MVC+");
Console.WriteLine(book1);
var book2 = books.FirstOrDefault(b => b.Title == "C# Advanced Topics");
Console.WriteLine(book2.Title + " " + book2.Price);
var book3 = books.LastOrDefault(b => b.Title == "C# Advanced Topics");
Console.WriteLine(book3.Title + " " + book3.Price);
Console.WriteLine();
var books4 = books.Skip(2).Take(3);
foreach (var book in books4)
{
Console.WriteLine(book.Title);
}
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();
// LINQ query operators
// always start with from and end with select
var cheapBooks =
from b in books
where b.Price < 10
orderby b.Title
select b.Title;
foreach (var book in cheapBooks)
{
Console.WriteLine(book);
}
var singleBook = books.SingleOrDefault(b => b.Title == "Book 2"); // if there is no book2 it will return the default which is null
Console.WriteLine("Single book: " + singleBook.Title);
var firstBook = books.FirstOrDefault(b => b.Title == "Book 3");
Console.WriteLine("First book that has title Book 3: " + firstBook.Price); // default is null
var lastBook = books.LastOrDefault(b => b.Title == "Book 3");
Console.WriteLine("Last book that has title Book 3: " + lastBook.Price);
var pages = books.Skip(2).Take(3); // skips the first 2 books and takes the next 3
foreach (var pagedBook in pages)
{
Console.WriteLine(pagedBook.Title);
}
var count = books.Count();
Console.WriteLine("Count: " + count);
var maxPrice = books.Max(b => b.Price); // returns the book with the max price
Console.WriteLine("Max: " + maxPrice);
var sumPrice = books.Sum(b => b.Price);
Console.WriteLine("Total: " + sumPrice);
// 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);*/
// after using select for the title, book is now a string because it returns an
// IEnumerable of just the title of the books. This can no longer be used
/* foreach(var book in cheapBooks)
* Console.WriteLine(book.Title + " " + book.Price);*/
// without LINQ
/* var cheapBooks = new List<Book>();
* foreach(var book in books)
* {
* if (book.Price < 10)
* {
* cheapBooks.Add(book);
* Console.WriteLine(book.Title + " " + book.Price);
* }
* }*/
}