C# Edit string in file - delete a character (000)

Question

I am rookie in C#, but I need solve one Problem. I have several text files in Folder and each text files has this structure:

IdNr 000000100

Name Name

Lastname Lastname

Sex M

.... etc...

Load all files from Folder, this is no Problem ,but i need delete "zero" in IdNr, so delete 000000 and 100 leave there. After this file save. Each files had other IdNr , Therefore, it is harder :(

Yes, it is possible each files manual edit, but when i have 3000 files, this is not good :) Can C# one algorithm, which could this 000000 delete and leave only number 100?

Thank you All. Vaclav

So, thank you ALL ! But in the End I have this Code :-) :

using System.IO;

namespace name { public partial class Form1 : Form { public Form1() { InitializeComponent(); }

    private void Browse_Click(object sender, EventArgs e)
    {
        DialogResult dialog = folderBrowserDialog1.ShowDialog();
        if (dialog == DialogResult.OK)
            TP_zdroj.Text = folderBrowserDialog1.SelectedPath;

    }

    private void start_Click(object sender, EventArgs e)
    {

       try
       {
           foreach (string file in Directory.GetFiles(TP_zdroj.Text, "*.txt"))
           {
               string text = File.ReadAllText(file, Encoding.Default);

               text = System.Text.RegularExpressions.Regex.Replace(text, "IdNr    000*", "IdNr    ");
               File.WriteAllText(file, text, Encoding.Default);

           }
       }
           catch
       {
           MessageBox.Show("Warning...!");
               return;

           }

        {
            MessageBox.Show("Done");

        }

    }
}

}

Thank you ALL ! ;)

Answer 1

You can use int.Parse :

int number = int.Parse("000000100");
String withoutzeros = number.ToString();

According to your read/save file issue, do the files contain more than one record, is that the header or does each record is a list of key and value like "IdNr 000000100"? It's difficult to answer without these informations.

Edit : Here's a simple but efficient approach which should work if the format is strict:

var files = Directory.EnumerateFiles(path, "*.txt", SearchOption.TopDirectoryOnly);

foreach (var fPath in files)
{ 
    String[] oldLines = File.ReadAllLines(fPath); // load into memory is faster when the files are not really huge
    String key = "IdNr ";
    if (oldLines.Length != 0)
    {
        IList<String> newLines = new List<String>();
        foreach (String line in oldLines)
        {
            String newLine = line;
            if (line.Contains(key))
            {
                int numberRangeStart = line.IndexOf(key) + key.Length;
                int numberRangeEnd = line.IndexOf(" ", numberRangeStart);
                String numberStr = line.Substring(numberRangeStart, numberRangeEnd - numberRangeStart);
                int number = int.Parse(numberStr);
                String withoutZeros = number.ToString();
                newLine = line.Replace(key + numberStr, key + withoutZeros);
                newLines.Add(line);
            }
            newLines.Add(newLine);
        }
        File.WriteAllLines(fPath, newLines);
    }
}

Answer 2

These are the steps you would want to take:

• Loop each file
• Read file line by line
• for each line split on " " and remove leading zeros from 2nd element
• write the new line back to a temp file
• after all lines processed, delete original file and rename temp file
• do next file

(you can avoid the temp file part by reading each file in full into memory, but depending on your file sizes this may not be practical)

---

You can remove the leading zeros with something like this:

string s = "000000100";
s = s.TrimStart('0');

Answer 3

使用TrimStart

var trimmedText = number.TrimStart('0');

Answer 4

This should do it. It assumes your files have a .txt extension, and it removes all occurrences of "000000" from each file.

foreach (string fileName in Directory.GetFiles("*.txt"))
{
    File.WriteAllText(fileName, File.ReadAllText(fileName).Replace("000000", ""));
}

Answer 5

Simply, read every token from the file and use this method:

var token = "000000100";
var result = token.TrimStart('0');

You can write a function similar to this one:

static IEnumerable<string> ModifiedLines(string file) {
    string line;
    using(var reader = File.OpenText(file)) {
        while((line = reader.ReadLine()) != null) {
            string[] tokens = line.Split(new char[] { ' ' });
            line = string.Empty;
            foreach (var token in tokens)
            {
                line += token.TrimStart('0') + " ";
            }
            yield return line;
        }
    }
}

Usage:

File.WriteAllLines(file, ModifiedLines(file));