c# - 使用 linq 获取分组的逗号分隔值

Question

我想要第三列“项目”，其中包含分组的值。

var dic = new Dictionary<string, int>();
dic.Add("a", 1);
dic.Add("b", 1);
dic.Add("c", 2);
dic.Add("d", 3);

var dCounts =
    (from i in dic
    group i by i.Value into g
    select new { g.Key, count = g.Count()});

    var a = dCounts.Where(c => c.count>1 );

dCounts.Dump();
a.Dump();

此代码导致:

Key Count
1   2
2   1
3   1

我想要这些结果:

Key Count Items
1   2     a, b
2   1     c
3   1     d

Answer 1

    var dCounts =
        (from i in dic
            group i by i.Value into g
            select new { g.Key, count = g.Count(), Items = string.Join(",", g.Select(kvp => kvp.Key)) });

使用 string.Join(",", {array})，传入您的键数组。