List with distinct values inside only

Question

I have list of objects with properties Id and Name.

 foreach (var x in mydata)
 {                
    var model = new MyViewModel()
    {
       Id = x.Days.Id,
       Name = x.Days.Name                                   
    };                                    
    models.Add(model);
 }

I'm returning list (models) which has duplicate items, how can I return list of distinct items inside?

There are dozens of duplicates. – Tim Schmelter Mar 31 '14 at 12:43 — Tim Schmelter, Mar 31 '14 at 12:43

score 1 · Answer 1 · answered Mar 31 '14 at 12:44

If you want elements distinct by Id :

foreach (var x in mydata)
 {                
    var model = new MyViewModel()
    {
       Id = x.Days.Id,
       Name = x.Days.Name                                   
    };                                    
    if(!models.Contains(x=>x.Id==model.Id)
        models.Add(model);
 }

score 1 · Answer 2 · answered Mar 31 '14 at 12:46

You can use HashSet<T>, something like that:

// Ids that was used before
HashSet<int> Ids = new HashSet<int>();

foreach (var x in mydata) {                
  // Check for duplicates
  if (Ids.Contains(x.Days.Id))
    continue; // <- duplicate
  else
    Ids.Add(x.Days.Id);

  // Your code
  var model = new MyViewModel() {
    Id = x.Days.Id,

    Name = x.Days.Name                                   
  };                                    

  models.Add(model);
}

List with distinct values inside only

2 Answers2