In C#, say I have a class called Note with three String member variables.
public class Note
{
public string Title;
public string Author;
public string Text;
}
And I have a list of type Note:
List<Note> Notes = new List<Note>();
What would be the cleanest way to get a list of all distinct values in the Author column?
I could iterate through the list and add all values that aren't duplicates to another list of strings, but this seems dirty and inefficient. I have a feeling there's some magical Linq construction that'll do this in one line, but I haven't been able to come up with anything.
mcilist = (from mci in mcilist select mci).Distinct().ToList();
public class KeyNote
{
public long KeyNoteId { get; set; }
public long CourseId { get; set; }
public string CourseName { get; set; }
public string Note { get; set; }
public DateTime CreatedDate { get; set; }
}
public List<KeyNote> KeyNotes { get; set; }
public List<RefCourse> GetCourses { get; set; }
List<RefCourse> courses = KeyNotes.Select(x => new RefCourse { CourseId = x.CourseId, Name = x.CourseName }).Distinct().ToList();
By using the above logic, we can get the unique Course
s.
Jon Skeet has written a library called morelinq which has a DistinctBy()
operator. See here for the implementation. Your code would look like
IEnumerable<Note> distinctNotes = Notes.DistinctBy(note => note.Author);
Update: After re-reading your question, Kirk has the correct answer if you're just looking for a distinct set of Authors.
Added sample, several fields in DistinctBy:
res = res.DistinctBy(i => i.Name).DistinctBy(i => i.ProductId).ToList();
Distinct the Note class by Author
var DistinctItems = Note.GroupBy(x => x.Author).Select(y => y.First());
foreach(var item in DistinctItems)
{
//Add to other List
}
Source: Stackoverflow.com