using LINQ in C# to convert a List<string> to a List<char>

Question

I have a list of strings in C#, and want to create a list of unique characters that are in the strings in the list, using LINQ.

I have so far worked out how to turn the List into a List, but I can't work out how to get the LINQ to go further than that.

What I have so far is as follows:

List<string> dictionary = new List<string>(someArray);
List<string[]> uniqueCharacters = dictionary.ConvertAll(s => s.Split());

I believe I need to something along the lines of

List<char> uniqueCharacters =
     dictionary.ConvertAll(s => s.Split()).SelectAll(t, i=>t[i][0]);

Answer 1

You can use LINQ's SelectMany method, e.g.:

var list = new List<string> { "Foo", "Bar" };

var chars = list.SelectMany(s => s.ToCharArray());
var distinct = chars.Distinct();

Answer 2

Get your LinQ result and put it in loop, compare every char with in list of char.

foreach (string character in dictionary)
        {
            if (!(uniqueCharacters).Contains(character))
            {
                uniqueCharacters.Add(character);
            }
        }