Select records which has no day-off throughout the week in List - C#

问题

I have an Employee class which defined as this:

Employee
{
   public int Id { get; set; }
   public string Name { get; set; }
   public DateTime WorkDate { get; set; }
   public bool isOff { get; set; }
}

This is my class implementation and usage:

List<Employee> workers = new List<Employee>()
{
    new Employee { Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/11/2016"), IsOff = false},
    new Employee { Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/12/2016"), IsOff = false},
    new Employee { Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/13/2016"), IsOff = true},
    new Employee { Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/14/2016"), IsOff = false},
    new Employee { Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/15/2016"), IsOff = false},
    new Employee { Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/16/2016"), IsOff = false},
    new Employee { Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/17/2016"), IsOff = false},
    new Employee { Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/11/2016"), IsOff = false},
    new Employee { Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/12/2016"), IsOff = false},
    new Employee { Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/13/2016"), IsOff = false},
    new Employee { Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/14/2016"), IsOff = false},
    new Employee { Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/15/2016"), IsOff = false},
    new Employee { Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/16/2016"), IsOff = false},
    new Employee { Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/17/2016"), IsOff = false},
};

In the initialization above there is only 1 record that is off:

Id = 1, Name = "Emp 1" and the WorkDate = 4/13/2016

Now how can i get the id of an employee which has no day off throughout the week (from April 11-17)? Which is Id = 2

A LINQ solution is far better but i dont know how to do it.

UPDATED

To avoid confusion of the object Employee i changed it to EmployeeSchedule

class EmployeeSchedule
{
   public int Id { get; set; }
   public string Name { get; set; }
   public DateTime WorkDate { get; set; }
   public bool isOff { get; set; }
}

This is the implementation

List<EmployeeSchedule> workers = new List<EmployeeSchedule>()
{
    new EmployeeSchedule{ Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/11/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/12/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/13/2016"), IsOff = true},
    new EmployeeSchedule{ Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/14/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/15/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/16/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 1, Name = "Emp 1", WorkDate = Convert.ToDateTime("4/17/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/11/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/12/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/13/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/14/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/15/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/16/2016"), IsOff = false},
    new EmployeeSchedule{ Id = 2, Name = "Emp 2", WorkDate = Convert.ToDateTime("4/17/2016"), IsOff = false},
};

The selected answer is still applicable.

回答1:

Now how can i get the id of an employee which has no day off throughout the week (from April 11-17)? Which is Id = 2

You could use Linq extensions, and achieve this.

var empid = workers.GroupBy(g=> g.Id)           
                   .Where(x=>x.All(e=>!e.IsOff))
                   .Select(x=>x.Key)

回答2:

That means you need a fromDate, toDate, and you have to find the employees from the list subject to the condition that, WorkDate should be in between fromDate and toDate, and also isOff == false that means has no day off throughout the week So you can use the following snippet :

 DateTime fromDate = new DateTime(2016, 04, 11);
 DateTime toDate = new DateTime(2016, 04, 17);
 var noDayOfList = workers.GroupBy(x=> x.Id)
                          .Where(x =>
                                 x.All(y=> 
                                 y.WorkDate >= fromDate && 
                                 y.WorkDate <= toDate && 
                                 !y.isOff))
                          .Select(z=>z.Key).ToList();

回答3:

You can write something like this:

var startDate = new DateTime(2016,04,11);
var endDate = new DateTime(2016,04,17);

var ids = workers
    .Where(w => w.WorkDate >= startDate)
    .Where(w => w.WorkDate <= endDate)
    .GroupBy(w => w.Id)
    .Where(g => !g.Any(w => w.IsOff))
    .Select(g => g.Key);

Essentially:

Filter the rows you need (in this time frame)
Group by employee id
Make sure none of the rows in the group are marked IsOff
Select the grouping key (in this case, it'll be the Employee's Id)

Note though, it's a bit confusing calling the object Employee, as it really represents an employee's schedule, rather than an employee itself

回答4:

try, this you have two condition id and date but your id is sufficient for get your requirement,

List<string> resEmp = new List<string>();

foreach (var item in workers )
 {
     if (item.Id == 2 and item.IsOff == false)
      {
        resEmp.Add(item);
      }
 }

回答5:

Look at these code too.

i have defined a Model class of Employee to get the data,

maybe currently you need Id but in Future you can use another properties too.

public class Employee
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public DateTime WorkDate { get; set; }
        public bool IsOff { get; set; }
    }

and Code wtih Linq Expression,

 Employee objEmployee = new Employee();
 objEmployee.Id = workers
         .GroupBy(itm => itm.Id)
         .Where(itm => !itm.Any(m => m.IsOff))
         .Select(itm => itm.Key)
         .FirstOrDefault();

来源：https://stackoverflow.com/questions/36565288/select-records-which-has-no-day-off-throughout-the-week-in-listt-c-sharp

标签

linq

ienumerable

enumerable

Select records which has no day-off throughout the week in List<T> - C#

问题

回答1:

回答2:

回答3:

回答4:

回答5: