Extracting a list of objects that exist in another list objects using linq

Question

Linq noob here.

I have IList<Product> ApplicableProducts and a IList<Product> CurrentProducts.

I need to return a new IList<Product> of all CurrentProducts that exist in Applicable products.

I understand I need to be working with .Contains and .Any but getting a little lost.

Any tips appreciated

John Gietzen · Accepted Answer · 2010-02-12 14:13:48Z

4

var intersection = list1.Intersect(list2);

or

var intersection = list1.Where(i => list2.Contains(i));

answered Feb 12, 2010 at 14:13

John Gietzen

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2 Comments

Calling Intersect should be faster for large collections. (It uses a hashtable)

@SLaks: Yeah, I was going to speculate on that, but I wasn't sure. Thanks.

Anton Gogolev · Accepted Answer · 2010-02-12 14:12:11Z

2

Can be done without LINQ. Here:

var identical = applicableProducts.Intersect(currentProducts);

You may also want to supply your own IEqualityComparer.

answered Feb 12, 2010 at 14:12

Anton Gogolev

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That is using linq. Intersect is defined in the System.Linq namespace.