Question

I have a class and want to work with it as Lists: e.g. List<int>, List<string>, ... , List<T>
I have a class Randomizor which will take the collection data type that will be shuffled. How can I do so?

class Randomizor<T>
{
    public Randomizor()
    {

    }

    public Array Shuffle(Array toShuffle)
    {

    }
}

Answer 1

EDIT: I found two superior impementations after a little digging so I would suggest those in preference.

An extension method for this purpose and already been suggested previously here
I include the code paraphrased to Shuffle below.

public static IEnumerable<T> Shuffle<T> (this IEnumerable<T> source)
{     
    Random random = new Random ();     
    T [] copy = source.ToArray ();      
    for (int i = copy.Length - 1; i >= 0; i--) 
    {         
        int index = random.Next (i + 1);
        yield return copy [index];
        copy [index] = copy [i];
    }
}

---

And an interesting solution adapted from this linq approach

public static IEnumerable<T> Shuffle<T> (this IEnumerable<T> source)
{     
    Random random = new Random ();     
    return source.OrderBy(i => Random.Next()).AsEnumerable();
}

---

The orignal answer but slower than the edits

public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> sequence) 
{     
    Random random = new Random();
    List<T> copy = sequence.ToList();
    while (copy.Count > 0)
    {
        int index = random.Next(copy.Count);
        yield return copy[index];
        copy.RemoveAt(index);
    }
} 

If you like one of these you should up vote the linked answer.

If you are very concerned about randomness, you could upgrade to one of the RNG algorithms from the Crypto API and seed it with some non deterministic value, like somthing generated from recent mouse activity. I suspect that would be overkill and it would degrade performance.