Tutorial :dynamic string formatting using string.format and List.Count()



Question:

I have to print out some PDFs for a project at work. Is there way to provide dynamic padding, IE. not using a code hard-coded in the format string. But instead based on the count of a List.

Ex.

If my list is 1000 elements long, I want to have this:

Part_0001_Filename.pdf... Part_1000_Filename.pdf

And if my list is say 500 elements long, I want to have this formatting:

Part_001_Filename.pdf... Part_500_Filename.PDF

The reason for this is how Windows orders file names. It sorts them alphabetically left-to-right or right-to-left, So I must use the leading zero, otherwise the ordering in the folder is messed up.


Solution:1

The simplest way is probably to build the format string dynamically too:

static List<string> FormatFileNames(List<string> files)  {      int width = (files.Count+1).ToString("d").Length;        string formatString = "Part_{0:D" + width + "}_{1}.pdf";        List<string> result = new List<string>();        for (int i=0; i < files.Count; i++)      {          result.Add(string.Format(formatString, i+1, files[i]));      }      return result;  }  

This could be done slightly more simply with LINQ if you like:

static List<string> FormatFileNames(List<string> files)  {      int width = (files.Count+1).ToString("d").Length;              string formatString = "Part_{0:D" + width + "}_{1}.pdf";        return files.Select((file, index) =>                               string.Format(formatString, index+1, file))                  .ToList();  }  

Note:If u also have question or solution just comment us below or mail us on toontricks1994@gmail.com
Previous
Next Post »