lamda expression to change array.array elements into a List

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Hello folks.

I have an array of objects (Series) which has a property Books. Books returns an array of Book objects. I would like to construct a List of all the Books in all the Series. I have the following code, which works.

C#

var allBooks = new List<Book>();
foreach (var s in Series)
    allBooks.AddRange(s.Books.ToList());
return allBooks;

However, I was trying to it with a lamda expression:

return Series.Select(s => s.Books.Select(b => b)).ToList();

That didn't work - it told me I was trying to convert an IEnumerable<IEnumerable<Book>> to a List<book>.
As I said, the first bit of code works, but out of curiosity, is there a way to do this with lamda expressions and/or LINQ?

Posted 7-May-11 13:55pm

Clive D. Pottinger

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OriginalGriff · Answer 1 · 2011-05-07T21:07:00

In Linq it is pretty simple:

C#

List<book> GetListFromSeries(Series[] Series)
    {
    var w = from s in Series
            from b in s.Books
            select b;
    return w.ToList<book>();
    }
class Series
    {
    public Book[] Books = new Book[5];
    }
class Book
    {
    public string Title;
    }

[edit]Bloody HTML characters! - OriginalGriff[/edit]