LINQ - Compare List objects and List of strings

Question

I have a list of objects (List1) and list of string (List2 - list of Names of the objects)

I need to get all objects from List1 if the object.Name does not exists in List2

How can write this LINQ C#.?

Possible duplicate of [Quickest way to compare two List<>](https://stackoverflow.com/questions/12795882/quickest-way-to-compare-two-list). I realize this is `string` vs. `object`, but [Skeet's answer refers to that issue specifically in the comments as well](https://stackoverflow.com/questions/12795882/quickest-way-to-compare-two-list#comment60600663_12795900). — ruffin, Oct 15 '18 at 13:00

score 13 · Accepted Answer · edited Feb 09 '17 at 08:30

13

public class Class1
{
    public string Name {get;set;}
}

var List1 = new List<Class1>();
var List2 = new List<string>();
var result = List1.Where(x=>!List2.Contains(x.Name)).ToList();

Or:

var result = List1.Where(x=>!List2.Any(n=>n==x.Name)).ToList();

edited Feb 09 '17 at 08:30

Alper Tunga Arslan

569
3
10

answered Feb 09 '17 at 07:42

Maksim Simkin

9,561
4
36
49

score 0 · Answer 2 · answered Feb 09 '17 at 10:30

class Program
{
    static void Main(string[] args)
    {

        List<List1Class> listClass = new List<List1Class>();

        listClass.Add(new List1Class { ObjectName = "obj1" });
        listClass.Add(new List1Class { ObjectName = "obj2" });
        listClass.Add(new List1Class { ObjectName = "obj3" });
        listClass.Add(new List1Class { ObjectName = "obj4" });

        List<string> listString = new List<string>();
        listString.Add("obj2");
        listString.Add("obj4");
        listString.Add("obj5");

        var filterlist = listClass.Where(l => !listString.Contains(l.ObjectName)).ToList();

    }
}

class List1Class { public string ObjectName { get; set; }

    //Add other property
}

LINQ - Compare List objects and List of strings

2 Answers2