How do I clone a range of array elements to a new array?

You could add it as an extension method:

public static T[] SubArray<T>(this T[] data, int index, int length){    T[] result = new T[length];    Array.Copy(data, index, result, 0, length);    return result;}static void Main(){    int[] data = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };    int[] sub = data.SubArray(3, 4); // contains {3,4,5,6}}

Update re cloning (which wasn't obvious in the original question). If you really want a deep clone; something like:

public static T[] SubArrayDeepClone<T>(this T[] data, int index, int length){    T[] arrCopy = new T[length];    Array.Copy(data, index, arrCopy, 0, length);    using (MemoryStream ms = new MemoryStream())    {        var bf = new BinaryFormatter();        bf.Serialize(ms, arrCopy);        ms.Position = 0;        return (T[])bf.Deserialize(ms);    }}

This does require the objects to be serializable ([Serializable] or ISerializable), though. You could easily substitute for any other serializer as appropriate - XmlSerializer, DataContractSerializer, protobuf-net, etc.

Note that deep clone is tricky without serialization; in particular, ICloneable is hard to trust in most cases.

You can use Array.Copy(...) to copy into the new array after you've created it, but I don't think there's a method which creates the new array and copies a range of elements.

If you're using .NET 3.5 you could use LINQ:

var newArray = array.Skip(3).Take(5).ToArray();

but that will be somewhat less efficient.

See this answer to a similar question for options for more specific situations.

Have you considered using ArraySegment?

http://msdn.microsoft.com/en-us/library/1hsbd92d.aspx