使用LINQ对没有空格的数字序列进行分组

var array = new int[] { 1, 2, 3, 4, 7, 8, 11, 15, 16, 17, 18 };var result = string.Join(",", array    .Distinct()    .OrderBy(x => x)    .GroupAdjacentBy((x, y) => x + 1 == y)    .Select(g => new int[] { g.First(), g.Last() }.Distinct())    .Select(g => string.Join("-", g)));

与

public static class LinqExtensions{    public static IEnumerable<IEnumerable<T>> GroupAdjacentBy<T>(        this IEnumerable<T> source, Func<T, T, bool> predicate)    {        using (var e = source.GetEnumerator())        { if (e.MoveNext()) {     var list = new List<T> { e.Current };     var pred = e.Current;     while (e.MoveNext())     {         if (predicate(pred, e.Current))         {  list.Add(e.Current);         }         else         {  yield return list;  list = new List<T> { e.Current };         }         pred = e.Current;     }     yield return list; }        }    }}