How to remove from list every duplicate Value in certain part of list?

Question

I got an List which got Data from an class, that has this propertys:

  public string ExtraInfo { get; set; }
    public string Teil { get; set; }
    public decimal Preis { get; set; }

after I added Data to this list I have the Problem that in Column "Teil" a lot of duplicates are.

I want to remove every duplicate from "Teil" and when its removing it should remove the whole row with "Preis" and "ExtraInfo" from this row.

Normally I would think of distinct but that seems just to delete If the full row has an duplicate.

List example:

Example

Does anyone got an Idea or an tip how to achieve this?

Answer 1

You can use DistinctBy method of type List. (Check Documentation). It will apply Distinct method only based on Teil attribute.

List<Data> examples = new()
{
    new Data { ExtraInfo = "InfoA", Teil = "TeilA", Preis = 0 },
    new Data { ExtraInfo = "InfoA", Teil = "TeilA", Preis = 0 },
    new Data { ExtraInfo = "InfoA", Teil = "TeilB", Preis = 0 },
    new Data { ExtraInfo = "InfoA", Teil = "TeilA", Preis = 0 },
};

var result = examples.DistinctBy(data => data.Teil).ToList();
result.ForEach(res => Console.WriteLine($"ExtraInfo: {res.ExtraInfo}, Teil: {res.Teil}, Preis: {res.Preis}"));
// Output result :
// ExtraInfo: InfoA, Teil: TeilA, Preis: 0
// ExtraInfo: InfoA, Teil: TeilB, Preis: 0