Convert parts of the string into lower case

Question

I have a string like this:

string str = "[Title] [A] The GODFATHER [B] Inception [C] Finding Nemo [D] BRAVE [/Title]";

I want to convert all the characters inside the square brackets into lower case, like so:

"[title] [a] The GODFATHER [b] Inception [c] Finding Nemo [d] BRAVE [/title]"

I am thinking of using regular expression but not sure how to use it. Please advice.

Vulpes · Answer

Try this which uses Regex.Replace with a MatchEvaluator delegate: using System; using System.Text.RegularExpressions; class Test { static void Main() { string str = [Title] [A] The GODFATHER [B] Inception [C] Finding Nemo [D] BRAVE [/Title]; str = Regex.Replace(str @\[.+?] ReplaceMatch); Console.WriteLine(str); Console.ReadKey(); } static string ReplaceMatch(Match m) { string s = m.Value; s = m.Value.Substring(1 s.Length - 2).ToLower(); return String.Format([{0}] s); } }