How to rename dynamically file name

Question

I want to have the file names like this: Nr[first number in file]-[last number in file].txt.

this I have:

   static void Main(string[] args)
        {


            const int linesPerFile = 10;
            string path = @"G:\Folder";
            const string destinationFileName = @"G:\Folder\File-Part-{0}.txt";
            var bans = BankAcoutNumbers.BANS;
            string tempFile;
            //string fileName = "File";
            var maxNumberOfFiles = 10;
            Stopwatch timer = new Stopwatch();



                var fileCounter = 0;

                if (!Directory.Exists(path))
                {
                   DirectoryInfo di = Directory.CreateDirectory(path);
                }

                var destiNationFile = new StreamWriter(string.Format(destinationFileName, fileCounter + 1));
                try
                {

                    // foreach (var bank in BankAcoutNumbers.BANS.Take(100))
                    //{
                    var lineCounter = 0;
                    string line;

                    while (fileCounter <= maxNumberOfFiles)
                    {
                        timer.Start();
                        foreach (var bank in BankAcoutNumbers.BANS.Take(100))
                        {
                            if (lineCounter % linesPerFile == 0)
                            {
                                //lineCounter = 0;
                                destiNationFile.Flush();                                
                                destiNationFile.Dispose();
                                destiNationFile = new StreamWriter(string.Format(destinationFileName, fileCounter + 1));
                                fileCounter++;
                            }

                            destiNationFile.WriteLine(bank);
                            lineCounter++;



                        }

                        fileCounter++;

                        //}


                    }


                    timer.Stop();
                    // Console.WriteLine(BankAcoutNumbers.BANS.Count());
                    Console.WriteLine(timer.Elapsed.Seconds);
                }
                catch (Exception)
                {

                    throw;
                }



            // Keep the console window open in debug mode.

            System.Console.WriteLine("Press any key to exit.");
            System.Console.ReadKey();
        }

So the first file contains the numbers:

100000002 100000010 100000029 100000037 100000045 100000053 100000061 100000088 100000096 100000118

so the file name has to be then: Nr[100000002]-[100000118].txt

Thank you

and second file contains the numbers:

100000126 100000134 100000142 100000150 100000169 100000177 100000185 100000193 100000207 100000215

Answer 1

Unless your files are very long, you can simply read their full content into the memory, split up their content and rename them.

            // Get files
            DirectoryInfo di = new DirectoryInfo (@"c:\my\path");
            var files = di.GetFiles();

            // Loop through files
            foreach (var file in files) 
            {
                // Read file
                string content = File.ReadAllText (file.FullName);

                // Split text (add as many separators as you want, I'm using
                // whitespace just like in your example)
                string[] numbers = content.Split (' ');

                // First number is numbers[0]
                // Last number is numbers[numbers.Length - 1]

                // Rename file
                File.Move(file.FullName, string.Format("Nr{0}-{1}.txt", numbers[0], numbers[numbers.Length - 1]));
            }