How to compare 2 List objects to get the missing value from the List

Question

How do I use the \"NOT IN\" to get the missing data, to be added to \"foo\" List.

var accessories = new List(); 
var foo = new List()         


        

Answer 1

You can combine Concat and Distinct to do this:

foo = foo.Concat(accessories).Distinct().ToList();

Edit: Or Except as others have pointed out, which seems to be the superior choice for this case.