Create batches in linq

Question

Can someone suggest a way to create batches of a certain size in linq?

Ideally I want to be able to perform operations in chunks of some configurable amount.

Answer 1

All of the above perform terribly with large batches or low memory space. Had to write my own that will pipeline (notice no item accumulation anywhere):

public static class BatchLinq {
    public static IEnumerable> Batch(this IEnumerable source, int size) {
        if (size <= 0)
            throw new ArgumentOutOfRangeException("size", "Must be greater than zero.");

        using (IEnumerator enumerator = source.GetEnumerator())
            while (enumerator.MoveNext())
                yield return TakeIEnumerator(enumerator, size);
    }

    private static IEnumerable TakeIEnumerator(IEnumerator source, int size) {
        int i = 0;
        do
            yield return source.Current;
        while (++i < size && source.MoveNext());
    }
}

Edit: Known issue with this approach is that each batch must be enumerated and enumerated fully before moving to the next batch. For example this doesn't work:

//Select first item of every 100 items
Batch(list, 100).Select(b => b.First())