public static T RandomOrDefault <T>(this IEnumerable <T> things, Battleship.ShuggyCoUk.Simple.Rand rand)
{
int count = things.Count();
if (count == 0)
{
return(default(T));
}
return(things.ElementAt(rand.Next(count)));
}
public static IEnumerable <T> Shuffle <T>(this IEnumerable <T> source, Battleship.ShuggyCoUk.Simple.Rand rand)
{
T[] elements = source.ToArray();
// Note i > 0 to avoid final pointless iteration
for (int i = elements.Length - 1; i > 0; i--)
{
// Swap element "i" with a random earlier element it (or itself)
int swapIndex = rand.Next(i + 1);
T tmp = elements[i];
elements[i] = elements[swapIndex];
elements[swapIndex] = tmp;
}
// Lazily yield (avoiding aliasing issues etc)
foreach (T element in elements)
{
yield return(element);
}
}