Most efficient way to compare two lists and delete the same

Question

I want to compare two lists and get the valid words into a new list.

var words = new List<string>();
var badWords = new List<string>();

//this is just an example list. actual list does contain 700 records
words.Add("Apple");
words.Add("Moron");
words.Add("Seafood");
words.Add("Cars");
words.Add("Chicken");
words.Add("Twat");
words.Add("Watch");
words.Add("Android");
words.Add("c-sharp");
words.Add("Fool");

badWords.Add("Idiot");
badWords.Add("Retarded");
badWords.Add("Twat");
badWords.Add("Fool");
badWords.Add("Moron");

I am looking for most efficient way to compare the lists and put all the 'good' words into a new list. The finalList shouldn't contain "Moron", "Twat" and "Fool".

var finalList = new List<string>();

Or is it unnecessary to create a new List? I am happy to hear your ideas!

Thank you in advance

Answer 1

Use EnumerableExcept function storing in System.Linq namespace

finalList = words.Except(badWords).ToList();

Most efficient way to save your time and also the fastest way to do it, because Except implementation uses Set, which is fast