Question

我想要第三列“items”，其中包含已分组的值。

Dictionary<string, int> 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})，传入您的数组键。

Answer 2

您可以使用：

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

通过分组（值g）创建的结果具有一个属性Key，可以为您提供密钥，但它还实现了IEnumerable<T>，允许您访问组中的各个值。如果只返回g，则可以使用foreach迭代所有值，或使用LINQ处理它们。

这是一个简单的转储函数来演示：

foreach(var el in dCounts) {
  Console.Write(" - {0}, count: {1}, values:", el.Key, el.Count);
  foreach(var item in el.Values) Console.Write("{0}, ", item);
|

Answer 3

from i in dic 
group i.Key by i.Value into g 
select new
{
  g.Key,
  count = g.Count(),
  items = string.Join(",", g.ToArray())
});

使用linq获取分组的逗号分隔值

3 个答案: