Linq查找指定重复次数的键

        var list = new List<dynamic>();        for (int i = 0; i < 10; i++)        {            if (i < 3)            {                list.Add(new { a = 1, b = 2 });            }            else            {                list.Add(new { a = i, b = 2 });            }        }        var ll = list.GroupBy(o => o.a).Select(g => (new { name = g.Key, count = g.Count() })).Where(o=>o.count>=3).Select(o=>o.name).ToList<object>();