Efficent way List order by element index

Question

I have a List of Books which below :

List<book> books = new List<book>() 
{ 
    new() { bookName = "wingbook" }, 
    new() { bookName = "Peter Pan" },
    new() { bookName = "Apple Pie" },
    new() { bookName = "Zebra" } 
}

I want to find way to order by books by index descending order (not a book name). Expected result is

result = {
    { bookName = "Zebra" },
    { bookName = "Apple Pie" },
    { bookName = "Peter Pan" },
    { bookName = "wingbook" }
}

Can I know how to write it simplified it ?

Answer 1

You simply want to reverse the list? Then use:

books.Reverse();

or you could use the Reverse extension method, that does not modify the original collection:

var ordered = books.AsEnumerable().Reverse();

You could also use the Select overload to get the index:

books = books 
    .Select((book, index) => (book, index))
    .OrderByDescending(x => x.index)
    .Select(x => x.book)
    .ToList();