Can you enumerate a collection in C# out of order?

Question

Is there a way to use a foreach loop to iterate through a collection backwards or in a completely random order?

Answer 1

As other answers mention, the Reverse() extension method will let you enumerate a sequence in reverse order.

Here's a random enumeration extension method:

public static IEnumerable OrderRandomly(this IEnumerable sequence)
{
    Random random = new Random();
    List copy = sequence.ToList();

    while (copy.Count > 0)
    {
        int index = random.Next(copy.Count);
        yield return copy[index];
        copy.RemoveAt(index);
    }
}

Your usage would be:

foreach (int n in Enumerable.Range(1, 10).OrderRandomly())
    Console.WriteLine(n);