单列上的Lambda表达式groupby并获取所有列的orderby计数

Question

在这里我的查询是我有一个重复数据的列表，对此，我想在groupby列上执行FName子句，并通过递减计数顺序显示并显示该记录的所有记录特定列表

        List<Employee> empList = new List<Employee>();
        empList.Add(new Employee() { ID = 1, FName = "John", Age = 23, Sex = 'M' });
        empList.Add(new Employee() { ID = 2, FName = "Mary", Age = 25, Sex = 'F' });
        empList.Add(new Employee() { ID = 3, FName = "John", Age = 28, Sex = 'M' });
        empList.Add(new Employee() { ID = 4, FName = "Amber", Age = 23, Sex = 'M' });
        empList.Add(new Employee() { ID = 5, FName = "Kathy", Age = 25, Sex = 'M' });
        empList.Add(new Employee() { ID = 6, FName = "Lena", Age = 27, Sex = 'F' });
        empList.Add(new Employee() { ID = 7, FName = "John", Age = 28, Sex = 'M' });
        empList.Add(new Employee() { ID = 8, FName = "Kathy", Age = 27, Sex = 'F' });         

        var dup1 = empList
          .GroupBy(x => new { x.FName })
          .Select(group => new { Name = group.Key.FName, Count = group.Count() })
          .OrderByDescending(x => x.Count);

        foreach (var x in dup1)
        {
            Console.WriteLine(x.Count + " " + x.Name);
        }

从上面的代码中，我得到这样的输出：

但是我真正想要的是这样的：

Answer 1

您似乎希望组计数，然后是有关组中第一项的信息。如果是这种情况，那么您可以简单地使用GroupBy对项目进行分组，然后在输出中捕获并显示该组中第一个项目的信息：

var groups = empList.GroupBy(e => e.FName).OrderByDescending(group => group.Count());

foreach (var group in groups)
{
    var first = group.First();
    Console.WriteLine($"{group.Count()} {first.FName}\t{first.Age} {first.Sex}");
}

输出

Answer 2

.Select(group => new
{
    Name = group.Key.FName, 
    Count = group.Count(),
    Age = group.First().Age,
    Sex = group.First().Gender
});