Using LINQ how can I check for an instance of a number in one array, in another array?

Question

I have a list of MyItem objects called myItems like this:

public class MyItem{
    public int[] category_ids;
    public string name;
}

List<MyItem> myItems;

I want to filter down the list of objects with a list of selected categories so that the filtered list contains ANY of the filter category ids:

int[] filter = { 1, 5, 6, 9 };

How would I do that using LINQ in one line? (if its even possible, I cant wrap my head around it!) I imagine something along the lines of:

IEnumerable<MyItem> filtered = myItems.Where(item => item.category_ids.Contains(xxx));

cuongle · Accepted Answer · 2012-10-04 12:12:02Z

2

var filtered = myItems.Where(x => x.category_ids.Intersect(filter)
                                          .Any());

answered Oct 4, 2012 at 12:12

cuongle

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Comments

Euphoric · Accepted Answer · 2012-10-04 12:10:26Z

2

Needs one more method call:

IEnumerable<MyItem> filtered = myItems.Where(item => item.category_ids.Any(x=>filter.Contains(x));

answered Oct 4, 2012 at 12:10

Euphoric

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Wiktor Zychla · Accepted Answer · 2012-10-04 12:10:40Z

2

Another option than the one already presented:

var filtered = myItems.Where( item => item.category_ids.Intersect( filter ).Count() > 0 );

answered Oct 4, 2012 at 12:10

Wiktor Zychla

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