Remove all characters after the last letter

Question

The following simple program will find the last letter in a string that a user enters and then remove everything after that point. So, if a person enters one string.... everything after the g should be removed. I've got the following as a little program:

class Program
{
    static void Main(string[] args)
    {
        Console.Write("Enter in the value of the string: ");
        List<char> charList = Console.ReadLine().Trim().ToList();

        int x = charList.LastIndexOf(charList.Last(char.IsLetter)) ;
        Console.WriteLine("this is the last letter {0}", x);
        Console.WriteLine("This is the length of the string {0}", charList.Count);
        Console.WriteLine("We should have the last {0} characters removed", charList.Count - x);

        for (int i = x; i < charList.Count; i++)
        {
            charList.Remove(charList[i]);
        }

        foreach (char c in charList)
        {
            Console.Write(c);
        }
        Console.ReadLine();
    }
}

I've tried numerous variations of this and none of them getting it exactly write. This particular program with an input of string.... the output of the program is strin.. So somehow it's leaving on what it should be taking away and it's actually taking away letters that it shouldn't. Can anyone give an indication as to why this is happening? The desired output, again should be string.

Answer 1

Try this:

string input = Console.ReadLine();                // ABC.ABC.
int index = input.Select((c, i) => new { c, i })
                 .Where(x => char.IsLetter(x.c))
                 .Max(x => x.i);
string trimmedInput = input.Substring(0, index + 1);
Console.WriteLine(trimmedInput);                  // ABC.ABC