Question

我有一个EmployeeSchedule班级

public class EmployeeSchedule
{
    public string EmpId { get; set; }
    public string Shift { get; set; }
    public DayOfWeek Day{ get; set; }
}

通过此实施：

List<EmployeeSchedule> ess = new List<EmployeeSchedule>
{
    new EmployeeSchedule { EmpId = "1001", Shift = "OFF", Day = Sunday },
    new EmployeeSchedule { EmpId = "1001", Shift = "MOR", Day = Monday },
    new EmployeeSchedule { EmpId = "1001", Shift = "MOR", Day = Tuesday },
    new EmployeeSchedule { EmpId = "1001", Shift = "MOR", Day = Wednesday },
    new EmployeeSchedule { EmpId = "1001", Shift = "MOR", Day = Thursday },
    new EmployeeSchedule { EmpId = "1001", Shift = "MOR", Day = Friday },
    new EmployeeSchedule { EmpId = "1001", Shift = "MOR", Day = Saturday },
    new EmployeeSchedule { EmpId = "1002", Shift = "SWN", Day = Sunday },
    new EmployeeSchedule { EmpId = "1003", Shift = "GY", Day = Sunday },
    new EmployeeSchedule { EmpId = "1004", Shift = "GY", Day = Sunday },
    new EmployeeSchedule { EmpId = "1005", Shift = "MOR", Day = Sunday },
    new EmployeeSchedule { EmpId = "1005", Shift = "MOR", Day = Monday },
    new EmployeeSchedule { EmpId = "1005", Shift = "MOR", Day = Tuesday },
    new EmployeeSchedule { EmpId = "1005", Shift = "MOR", Day = Wednesday },
    new EmployeeSchedule { EmpId = "1005", Shift = "MOR", Day = Thursday },
    new EmployeeSchedule { EmpId = "1006", Shift = "SWN", Day = Sunday },
    new EmployeeSchedule { EmpId = "1007", Shift = "MOR", Day = Sunday }
}

我希望列表中的某个项目符合COUNT条件：

SHIFT "MOR"次数小于2的情况：这会让我EmpId = "1007"
SHIFT "MOR"次数等于5的情况：这会让我EmpId = "1005"

到目前为止，我尝试了这一点，但我真的不知道在哪里或如何将COUNT作为标准。

var id = ess.Where(x => x.Shift == "MOR").FirstOrDefault();

我怎样才能实现这个目标？

Answer 1

您可以使用Where和GroupBy + Count：

var empIdGroupsWithMorShift = ess
    .Where(es => es.Shift == "MOR")
    .GroupBy(es => es.EmpId);
var lessTwo = empIdGroupsWithMorShift
    .Where(g => g.Count() < 2)
    .Select(g => new  { EmpId = g.Key, Count = g.Count()} );
var five = empIdGroupsWithMorShift
    .Where(g => g.Count() == 5)
    .Select(g => new { EmpId = g.Key, Count = g.Count() });

如果您只想要一个字符串作为评论的结果，您可以使用String.Join：

string five = String.Join(",", empIdGroupsWithMorShift
    .Where(g => g.Count() == 5)
    .Select(g => g.Key));  // "1005"

Answer 2

您可以尝试使用 Linq ：

  var result2 = ess
   .GroupBy(record => record.EmpId)
   .Where(chunk => chunk.Count(record => record.Shift == "MOR") < 2)
   .Select(chunk => chunk.Key);

  var result5 = ess
    .GroupBy(record => record.EmpId)
    .Where(chunk => chunk.Count(record => record.Shift == "MOR") == 5)
    .Select(chunk => chunk.Key);

  // Test
  // 1005
  Console.Write(String.Join(Environment.NewLine, result5));

Answer 3

要扩展Tim Schmelter的答案，您可以创建一种扩展方法，以便更轻松地过滤数据

public static class ExtensionMethods
{
    public static string[] GetByShiftCount(this List<EmployeeSchedule> list, string shift, Func<int, bool> filter)
    {
        return list.Where(x => x.Shift == shift)
                   .GroupBy(x => x.EmpId)
                   .Where(g => filter(g.Count()))
                   .Select(g => g.Key)
                   .ToArray();
    }
}

你可以像这样使用它

string[] EmpIds = ess.GetByShiftCount("MOR", x => x < 2);
string[] EmpIds = ess.GetByShiftCount("MOR", x => x == 5);

Answer 4

获取列表，您必须致电ToList(); 你可以像这样计算

var mylist = ess.Where(c=>c.Shift =="MOR").ToList();

if(mylist.count > 5

//逻辑到这里

Answer 5

希望这将是解决方案（更新）：

            var splitResponse = xmlhttp.responseText.split( "Indiviual" );
    var firstDropdownContent = splitResponse[0];
         var secondDropdownContent = splitResponse[1];
        // var thirdDropdownContent = splitResponse[2];
             alert (firstDropdownContent);
             alert (secondDropdownContent);
             //alert (thirdDropdownContent);

Answer 6

试试这个......

 var result = ess.GroupBy(x => x.EmpId).Where(x => x.Count() < 2).SelectMany(x => x).Where(x => x.Shift == "MOR");

LINQ - 查找列表中的某些项<t>按计数标准

6 个答案: