Question

我有一个List对象，其中包含Id值，例如它包含： 1,2,10,1,23,11,1,4,2,2，...等我需要找出有多少次“1”，“2”，......等已经发生在C＃中使用Linq

请帮助。

Answer 1

使用Enumerable.GroupBy非常简单：

var grouped = list.GroupBy(x => x);

foreach (var group in grouped)
{
    Console.WriteLine("{0} appears {1} times", group.Key, group.Count());
}

或者：

var query = list.GroupBy(x => x, (x, g) => new { Key = x, Count = g.Count() }));

foreach (var result in query)
{
    Console.WriteLine("{0} appears {1} times", result.Key, result.Count);
}

（区别在于我们真正将组转换为结果。）

Answer 2

使用GroupBy：

var les = new[] { 1, 2, 10, 1, 23, 11, 1, 4, 2, 2 };

var result = les
    .GroupBy(i => i, (e, g) => new { Value = e, Count = g.Count() });

或使用替代语法：

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

Answer 3

 var l = new List<int> {1,2,10,1,23,11,1,4,2,2};
 l.GroupBy(i => i)
   .ToList()
   .ForEach(g => Console.WriteLine("{0} : {1}", g.Key, g.Count()));

Answer 4

var list = new List<int> { 1, 2, 10, 1, 23, 11, 1, 4, 2, 2, };
var groups = list.GroupBy(i => i);
foreach (var group in groups)
    Console.WriteLine("{0} occurs {1} times", group.Key, group.Count());

使用linq </int>列出<int>过滤

4 个答案: