using System; using System.Text.RegularExpressions; public class Test { public static void Main() { Regex regex = new Regex(@"\b\d{4}-\d{3,4}\b"); foreach (Match match in regex.Matches("9000-001 a 9999-999")) { Console.WriteLine("Encontrei '{0}' na posição {1}", match.Value, match.Index); } } }