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Author Topic: C# Rename file with incrementing number - file (1).ext  (Read 3982 times)

Renegade

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C# Rename file with incrementing number - file (1).ext
« on: July 25, 2014, 09:51:55 PM »
I've seen people posting code snippets, so here's one...

I was looking around for a way to increment a file name, and didn't come across anything that really worked all that well except for 1 that kind of worked. I've bolstered it up a bit & made it more robust.

Problem:

You want to quickly save file.ext, but not overwrite an existing file with that name. Obviously you want to add an increment for the file name: 1, 2, 3, etc. So you end up with something like this in a folder:

file.ext
file (1).ext
file (2).ext
etc.

Snippet:

This is a bit sloppy in a few places, but it's good enough.

NOTE: This comes out of writing some transcoding software, so the signature there is to allow passing in a file name along with a new file name extension, which is a bit sloppy for general purposes. Basically, you can change the file extension by passing in a different "ext" parameter.

If you don't want a new file extension, simply pass in an empty string for "ext".

Code: C# [Select]
  1. /// <summary>
  2. /// A function to add an incremented number at the end of a file name if a file already exists.
  3. /// </summary>
  4. /// <param name="file">The file. This should be the complete path.</param>
  5. /// <param name="ext">This can be empty.</param>
  6. /// <returns>An incremented file name. </returns>
  7. private string AppendFileNumberIfExists(string file, string ext)
  8. {
  9.         // This had a VB tidbit that helped to get this started.
  10.         // http://www.codeproject.com/Questions/212217/increment-filename-if-file-exists-using-csharp
  11.  
  12.         // If the file exists, then do stuff. Otherwise, we just return the original file name.
  13.         if (File.Exists(file)) {
  14.                 string folderPath = Path.GetDirectoryName(file); // The path to the file. No sense in dealing with this unecessarily.
  15.                 string fileName = Path.GetFileNameWithoutExtension(file); // The file name with no extension.
  16.                 string extension = string.Empty; // The file extension.
  17.                 // This lets us pass in an empty string for the file extension if required. i.e. It just makes this function a bit more versatile.
  18.                 if (ext == string.Empty) {
  19.                         extension = Path.GetExtension(file);
  20.                 }
  21.                 else {
  22.                         extension = ext;
  23.                 }
  24.  
  25.                 // at this point, find out if the fileName ends in a number, then get that number.
  26.                 int fileNumber = 0; // This stores the number as a number for us.
  27.                 // need a regex here - \(([0-9]+)\)$
  28.                 Regex r = new Regex(@"\(([0-9]+)\)$"); // This matches the pattern we are using, i.e. ~(#).ext
  29.                 Match m = r.Match(fileName); // We pass in the file name with no extension.
  30.                 string addSpace = " "; // We'll add a space when we don't have our pattern in order to pad the pattern.
  31.                 if (m.Success) {
  32.                         addSpace = string.Empty; // We have the pattern, so we don't add a space - it has already been added.
  33.                         string s = m.Groups[1].Captures[0].Value; // This is the single capture that we are looking for. Stored as a string.
  34.                         // set fileNumber to the new number.
  35.                         fileNumber = int.Parse(s); // Convert the number to an int.
  36.                         // remove the numbering from the string as we're constructing it again below.
  37.                         fileName = fileName.Replace("(" + s + ")", "");
  38.                 }                
  39.                
  40.                 // Start looping.
  41.                 do
  42.                 {
  43.                         fileNumber += 1; // Increment the file number that we have above.
  44.                         file = Path.Combine(folderPath, // Combine it all.
  45.                                                 String.Format("{0}{3}({1}){2}", // The pattern to combine.
  46.                                                                           fileName,         // The file name with no extension.
  47.                                                                           fileNumber,       // The file number.
  48.                                                                           extension,        // The file extension.
  49.                                                                           addSpace));       // A space if needed to pad the initial ~(#).ext pattern.
  50.                         }
  51.                 while (File.Exists(file)); // As long as the file name exists, keep looping.
  52.         }
  53.         return file;
  54. }

Just one of those typical jobs that nobody should have to bother doing again.
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ghendric

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Re: C# Rename file with incrementing number - file (1).ext
« Reply #1 on: February 02, 2016, 11:50:08 AM »
This version works pretty good too.
Code: C# [Select]
  1. private string GetNextFileName(string fileName) {
  2.             string extension = Path.GetExtension(fileName);
  3.             string pathName = Path.GetDirectoryName(fileName);
  4.             string fileNameOnly = Path.Combine(pathName, Path.GetFileNameWithoutExtension(fileName));
  5.             int i = 0;
  6.             // If the file exists, keep trying until it doesn't
  7.             while (File.Exists(fileName)) {
  8.                 i += 1;
  9.                 fileName = string.Format("{0}({1}){2}", fileNameOnly, i, extension);
  10.             }
  11.             return fileName;
  12.         }

Ath

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Re: C# Rename file with incrementing number - file (1).ext
« Reply #2 on: February 02, 2016, 01:51:37 PM »
This version works pretty good too.
Not if a path is prepended to the filename... :o