linq where list contains any in list

C#Linq

C# Problem Overview

Using linq, how can I retrieve a list of items where its list of attributes match another list?

Take this simple example and pseudo code:

List<Genres> listofGenres = new List<Genre>() { "action", "comedy" });   
var movies = _db.Movies.Where(p => p.Genres.Any() in listofGenres);

C# Solutions

Solution 1 - C#

Sounds like you want:

var movies = _db.Movies.Where(p => p.Genres.Intersect(listOfGenres).Any());

Solution 2 - C#

You can use a Contains query for this:

var movies = _db.Movies.Where(p => p.Genres.Any(x => listOfGenres.Contains(x));

Solution 3 - C#

If you use HashSet instead of List for listofGenres you can do:

var genres = new HashSet<Genre>() { "action", "comedy" };   
var movies = _db.Movies.Where(p => genres.Overlaps(p.Genres));

Solution 4 - C#

I guess this is also possible like this?

var movies = _db.Movies.TakeWhile(p => p.Genres.Any(x => listOfGenres.Contains(x));

Is "TakeWhile" worse than "Where" in sense of performance or clarity?

Solution 5 - C#

If the Genre is an Entity and has its own Properties such as Title, use the following code:

var listofGenresName = new List<string> { "action", "comedy" };
var movies = _db.Movies.Where(p => p.Genres.Any(x => listofGenresName.Any(g=> g == x.Title)));

Solution 6 - C#

Or like this

class Movie
{
  public string FilmName { get; set; }
  public string Genre { get; set; }
}

...

var listofGenres = new List<string> { "action", "comedy" };

var Movies = new List<Movie> {new Movie {Genre="action", FilmName="Film1"},
                new Movie {Genre="comedy", FilmName="Film2"},
                new Movie {Genre="comedy", FilmName="Film3"},
                new Movie {Genre="tragedy", FilmName="Film4"}};

var movies = Movies.Join(listofGenres, x => x.Genre, y => y, (x, y) => x).ToList();
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QuestionVictorView Question on Stackoverflow
Solution 1 - C#Jon SkeetView Answer on Stackoverflow
Solution 2 - C#BrokenGlassView Answer on Stackoverflow
Solution 3 - C#Efraim BartView Answer on Stackoverflow
Solution 4 - C#TrevorView Answer on Stackoverflow
Solution 5 - C#Hamed LohiView Answer on Stackoverflow
Solution 6 - C#slavaView Answer on Stackoverflow