BiasCorrectQ.Program.GetMatchingFile C# (CSharp) Method

        private static string GetMatchingFile(string file, string dir)
        {
            var list_files = Directory.GetFiles(dir).ToList();

            //assume files contain name of future file without the extension
            string pattern = Path.GetFileNameWithoutExtension(file);

            //search for pattern in list_files
            var files = list_files.Where(s => s.Contains(pattern)).ToList();
            if (files.Count != 1)
            {
            if (files.Count == 0)
            {
                Console.WriteLine(
                    string.Format("error: no matching file for pattern ({0}) in directory - {1}",
                                  pattern, dir));
            }
            else
            {
                Console.WriteLine(
                    string.Format("error: multiple files match pattern ({0}) in directory - {1}",
                                  pattern, dir));
            }
            return string.Empty;
            }

            return files[0];
        }