Grouping consecutive integers in C#

Quick post: an extension method to group consecutive integers:

/// <summary>
/// Groups consecutive integers. Requires asc-ordered list
/// </summary>
/// <param name="list">ASC-ordered list of integers</param>
/// <returns></returns>
public static IEnumerable<IEnumerable<int>> GroupConsecutive(this IEnumerable<int> list) {
    var group = new List<int>();
    foreach (var i in list) {
        if (group.Count == 0 || i - group[group.Count - 1] <= 1)
            group.Add(i);
        else {
            yield return group;
            group = new List<int> {i};
        }
    }
    yield return group;
}

Sample usage:

var groups = new[] {1, 2, 4, 5, 6, 9}.GroupConsecutive();
foreach (var g in groups)
    Console.WriteLine("group: {0}", string.Join(",", g.Select(x => x.ToString()).ToArray()));

which prints out:

group: 1,2
group: 4,5,6
group: 9