I\'ve got a list of People that are returned from an external app and I\'m creating an exclusion list in my local app to give me the option of manually removing people from the
var thisList = new List{ "a", "b", "c" };
var otherList = new List {"a", "b"};
var theOnesThatDontMatch = thisList
.Where(item=> otherList.All(otherItem=> item != otherItem))
.ToList();
var theOnesThatDoMatch = thisList
.Where(item=> otherList.Any(otherItem=> item == otherItem))
.ToList();
Console.WriteLine("don't match: {0}", string.Join(",", theOnesThatDontMatch));
Console.WriteLine("do match: {0}", string.Join(",", theOnesThatDoMatch));
//Output:
//don't match: c
//do match: a,b
Adapt the list types and lambdas accordingly, and you can filter out anything.
https://dotnetfiddle.net/6bMCvN