shuffle (rearrange randomly) a List [dupli

Question

This question already has an answer here:

• Randomize a List<T> 18 answers

I need to rearrange my List array, it has a non-determinable number of elements in it.

Can somebody give me example of how i do this, thanks

Answer 1

List<Foo> source = ...
var rnd = new Random();
var result = source.OrderBy(item => rnd.Next());

Obviously if you want real randomness instead of pseudo-random number generator you could use RNGCryptoServiceProvider instead of Random.

Answer 2

This is an extension method that will shuffle a List<T>:

    public static void Shuffle<T>(this IList<T> list) {
        int n = list.Count;
        Random rnd = new Random();
        while (n > 1) {
            int k = (rnd.Next(0, n) % n);
            n--;
            T value = list[k];
            list[k] = list[n];
            list[n] = value;
        }
    }