Get distinct parameters from a List

Question

I have a CarData object with the following properties:
PrimaryKey Make Model Year Drivetrain Country

I have about 1000 of these CarData objects in a List :
List<CarData> CarObjects

Is there a simple way to get a list of the distinct Makes?

Possible Duplicate: [Linq Distinct() by name for populate a dropdown list with name and value](http://stackoverflow.com/q/912188/299327) — Ryan Gates, Feb 14 '13 at 15:31

score 4 · Accepted Answer · answered Feb 14 '13 at 15:28

4

var makes = CarObjects.Select(car => car.Make).Distinct();

This transforms the list from a list of CarData to a list of Makes, and then just finds the distinct values of the new list.

answered Feb 14 '13 at 15:28

Bobson

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score 2 · Answer 2 · answered Feb 14 '13 at 15:29

2

You can use Linq:

CarObjects.Select ( c => c.Make ).Distinct().ToList()

answered Feb 14 '13 at 15:29

Stephan Bauer

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NominSim · Answer 3 · 2013-02-14T15:35:11.930

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var makeList = CarObjects.Select(a => a.Make).Distinct();

Or

List<MakeEnum> = CarObjects.Select(a => a.Make).Distinct().ToList();

As an extra bit of advice, you may want to consider having Make be an enum, since there are (presumably) a finite (and rather small) number of possible makes of cars, instead of piling them into Strings. (You don't make a mention of what kind of property Make is, so maybe you are already doing this).

edited Feb 14 '13 at 15:35

answered Feb 14 '13 at 15:28

NominSim

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@DanielHilgarth The call to `Distinct` was aded in a later edit. – Daniel Kelley Feb 14 '13 at 15:32

Get distinct parameters from a List

3 Answers3