How can I split an IEnumerable into groups of IEnumerable [duplicate]

This is a late reply to this thread, but here is a method that doesn’t use any temporary storage:

public static class EnumerableExt
{
    public static IEnumerable<IEnumerable<T>> Partition<T>(this IEnumerable<T> input, int blockSize)
    {
        var enumerator = input.GetEnumerator();

        while (enumerator.MoveNext())
        {
            yield return nextPartition(enumerator, blockSize);
        }
    }

    private static IEnumerable<T> nextPartition<T>(IEnumerator<T> enumerator, int blockSize)
    {
        do
        {
            yield return enumerator.Current;
        }
        while (--blockSize > 0 && enumerator.MoveNext());
    }
}

And some test code:

class Program
{
    static void Main(string[] args)
    {
        var someNumbers = Enumerable.Range(0, 10000);

        foreach (var block in someNumbers.Partition(100))
        {
            Console.WriteLine("\nStart of block.");

            foreach (int number in block)
            {
                Console.Write(number);
                Console.Write(" ");
            }
        }

        Console.WriteLine("\nDone.");
        Console.ReadLine();
    }
}

However, do note the comments below for the limitations of this approach:

1. If you change the foreach in the test code to
   foreach (var block in someNumbers.Partition(100).ToArray())
   then it doesn’t work any more.

2. It isn’t threadsafe.