How to convert System.Linq.Enumerable.WhereListIterator to List?

Question

In the below example, how can I easily convert eventScores to List so that I can use it as a parameter for prettyPrint?

Answer 1

var evenScores = scores.Where(i => i % 2 == 0).ToList();

Doesn't work?

Answer 2

By the way why do you declare prettyPrint with such specific type for scores parameter and than use this parameter only as IEnumerable (I assume this is how you implemented ForEach extension method)? So why not change prettyPrint signature and keep this lazy evaluated? =)

Like this:

Action<IEnumerable<int>, string> prettyPrint = (list, title) =>
{
    Console.WriteLine("*** {0} ***", title);
    list.ForEach(i => Console.WriteLine(i));
};

prettyPrint(scores.Where(i => i % 2 == 0), "Title");

Update:

Or you can avoid using List.ForEach like this (do not take into account string concatenation inefficiency):

var text = scores.Where(i => i % 2 == 0).Aggregate("Title", (text, score) => text + Environment.NewLine + score);

Answer 3

You'd use the ToList extension:

var evenScores = scores.Where(i => i % 2 == 0).ToList();