This simple method checks if a string ends with either of the values in an array of characters, and returns true if it does. Useful to add appropriate suffixes to words in standard form.

1.public static bool EndsIn(this string o, string[] c)
2.{
3.    foreach (string i in c) // Loop through the possible endings
4.    {
5.        if (o.EndsWith(i)) // If any matches
6.            return true; // Return true
7.    }
8.    return false;
9.}