We Keep Coding

Replacing a certain word in a text file

I know this has been asked a few times, but I have seen a lot of regex etc., and I'm sure there is another way to do this with just a stream reader/writer. Below is my code. I'm trying to replace "tea" with the word "cabbage". Can somebody help? I believe I have the wrong syntax.
namespace Week_9_Exer_4
{
class TextImportEdit
{
public void EditorialControl()
{
string fileName;
string lineReadFromFile;
Console.WriteLine("");
// Ask for the name of the file to be read
Console.Write("Which file do you wish to read? ");
fileName = Console.ReadLine();
Console.WriteLine("");
// Open the file for reading
StreamReader fileReader = new StreamReader("C:\\Users\\Greg\\Desktop\\Programming Files\\story.txt");
// Read the lines from the file and display them
// until a null is returned (indicating end of file)
lineReadFromFile = fileReader.ReadLine();
Console.WriteLine("Please enter the word you wish to edit out: ");
string editWord = Console.ReadLine();
while (lineReadFromFile != null)
{
Console.WriteLine(lineReadFromFile);
lineReadFromFile = fileReader.ReadLine();
}
String text = File.ReadAllText("C:\\Users\\Greg\\Desktop\\Programming Files\\story.txt");
fileReader.Close();
StreamWriter fileWriter = new StreamWriter("C:\\Users\\Greg\\Desktop\\Programming Files\\story.txt", false);
string newText = text.Replace("tea", "cabbage");
fileWriter.WriteLine(newText);
fileWriter.Close();
}
}
}

If you don't care about memory usage:
string fileName = #"C:\Users\Greg\Desktop\Programming Files\story.txt";
File.WriteAllText(fileName, File.ReadAllText(fileName).Replace("tea", "cabbage"));
If you have a multi-line file that doesn't randomly split words at the end of the line, you could modify one line at a time in a more memory-friendly way:
// Open a stream for the source file
using (var sourceFile = File.OpenText(fileName))
{
// Create a temporary file path where we can write modify lines
string tempFile = Path.Combine(Path.GetDirectoryName(fileName), "story-temp.txt");
// Open a stream for the temporary file
using (var tempFileStream = new StreamWriter(tempFile))
{
string line;
// read lines while the file has them
while ((line = sourceFile.ReadLine()) != null)
{
// Do the word replacement
line = line.Replace("tea", "cabbage");
// Write the modified line to the new file
tempFileStream.WriteLine(line);
}
}
}
// Replace the original file with the temporary one
File.Replace("story-temp.txt", "story.txt", null);

In the end i used this : Hope it can help out others
public List<string> EditorialResponse(string fileName, string searchString, string replacementString)
{
List<string> list = new List<string>();
using (StreamReader reader = new StreamReader(fileName))
{
string line;
while ((line = reader.ReadLine()) != null)
{
line = line.Replace(searchString, replacementString);
list.Add(line);
Console.WriteLine(line);
}
reader.Close();
}
return list;
}
}
class Program
{
static void Main(string[] args)
{
TextImportEdit tie = new TextImportEdit();
List<string> ls = tie.EditorialResponse(#"C:\Users\Tom\Documents\Visual Studio 2013\story.txt", "tea", "cockrel");
StreamWriter writer = new StreamWriter(#"C:\Users\Tom\Documents\Visual Studio 2013\story12.txt");
foreach (string line in ls)
{
writer.WriteLine(line);
}
writer.Close();
}
}
}

Merging 2 Text Files in C#

Firstly, i'd just like to mention that I've only started learning C# a few days ago so my knowledge of it is limited.
I'm trying to create a program that will parse text files for certain phrases input by the user and then output them into a new text document.
At the moment, i have it the program searching the original input file and gathering the selected text input by the user, coping those lines out, creating new text files and then merging them together and also deleting them afterwards.
I'm guessing that this is not the most efficient way of creating this but i just created it and had it work in a logical manor for me to understand as a novice.
The code is as follows;
private void TextInput1()
{
using (StreamReader fileOpen = new StreamReader(txtInput.Text))
{
using (StreamWriter fileWrite = new StreamWriter(#"*DIRECTORY*\FIRSTFILE.txt"))
{
string file;
while ((file = fileOpen.ReadLine()) != null)
{
if (file.Contains(txtFind.Text))
{
fileWrite.Write(file + "\r\n");
}
}
}
}
}
private void TextInput2()
{
using (StreamReader fileOpen = new StreamReader(txtInput.Text))
{
using (StreamWriter fileWrite = new StreamWriter(#"*DIRECTORY*\SECONDFILE.txt"))
{
string file;
while ((file = fileOpen.ReadLine()) != null)
{
if (file.Contains(txtFind2.Text))
{
fileWrite.Write("\r\n" + file);
}
}
}
}
}
private static void Combination()
{
ArrayList fileArray = new ArrayList();
using (StreamWriter writer = File.CreateText(#"*DIRECTORY*\FINALOUTPUT.txt"))
{
using (StreamReader reader = File.OpenText(#"*DIRECTORY*\FIRSTFILE.txt"))
{
writer.Write(reader.ReadToEnd());
}
using (StreamReader reader = File.OpenText(#"*DIRECTORY*\SECONDFILE.txt"))
{
writer.Write(reader.ReadToEnd());
}
}
}
private static void Delete()
{
if (File.Exists(#"*DIRECTORY*\FIRSTFILE.txt"))
{
File.Delete(#"*DIRECTORY*\FIRSTFILE.txt");
}
if (File.Exists(#"*DIRECTORY*\SECONDFILE.txt"))
{
File.Delete(#"*DIRECTORY*\SECONDFILE.txt");
}
}
The output file that is being created is simply outputting the first text input followed by the second. I am wondering if it is possible to be able to merge them into 1 file, 1 line at a time as it is a consecutive file meaning have the information from Input 1 followed 2 is needed rather than all of 1 then all of 2.
Thanks, Neil.

To combine the two files content in an one merged file line by line you could substitute your Combination() code with this
string[] file1 = File.ReadAllLines("*DIRECTORY*\FIRSTFILE.txt");
string[] file2 = File.ReadAllLines("*DIRECTORY*\SECONDFILE.txt");
using (StreamWriter writer = File.CreateText(#"*DIRECTORY*\FINALOUTPUT.txt"))
{
int lineNum = 0;
while(lineNum < file1.Length || lineNum < file2.Length)
{
if(lineNum < file1.Length)
writer.WriteLine(file1[lineNum]);
if(lineNum < file2.Length)
writer.WriteLine(file2[lineNum]);
lineNum++;
}
}
This assumes that the two files don't contains the same number of lines.

try this method. You can receive three paths. File 1, File 2 and File output.
public void MergeFiles(string pathFile1, string pathFile2, string pathResult)
{
File.WriteAllText(pathResult, File.ReadAllText(pathFile1) + File.ReadAllText(pathFile2));
}
If the pathResult file exists, the WriteAllText method will overwrite it. Remember to include System.IO namespace.
Important: It is not recommended for large files! Use another options available on this thread.

If your input files are quite large and you run out of memory, you could also try wrapping the two readers like this:
using (StreamWriter writer = File.CreateText(#"*DIRECTORY*\FINALOUTPUT.txt"))
{
using (StreamReader reader1 = File.OpenText(#"*DIRECTORY*\FIRSTFILE.txt"))
{
using (StreamReader reader2 = File.OpenText(#"*DIRECTORY*\SECONDFILE.txt"))
{
string line1 = null;
string line2 = null;
while ((line1 = reader1.ReadLine()) != null)
{
writer.WriteLine(line1);
line2 = reader2.ReadLine();
if(line2 != null)
{
writer.WriteLine(line2);
}
}
}
}
}
Still, you have to have an idea how many lines you have in your input files, but I think it gives you the general idea to proceed.

Using a FileInfo extension you could merge one or more files by doing the following:
public static class FileInfoExtensions
{
public static void MergeFiles(this FileInfo fi, string strOutputPath , params string[] filesToMerge)
{
var fiLines = File.ReadAllLines(fi.FullName).ToList();
fiLines.AddRange(filesToMerge.SelectMany(file => File.ReadAllLines(file)));
File.WriteAllLines(strOutputPath, fiLines.ToArray());
}
}
Usage
FileInfo fi = new FileInfo("input");
fi.MergeFiles("output", "File2", "File3");

I appreciate this question is almost old enough to (up)vote (itself), but for an extensible approach:
const string FileMergeDivider = "\n\n";
public void MergeFiles(string outputPath, params string[] inputPaths)
{
if (!inputPaths.Any())
throw new ArgumentException(nameof(inputPaths) + " required");
if (inputPaths.Any(string.IsNullOrWhiteSpace) || !inputPaths.All(File.Exists))
throw new ArgumentNullException(nameof(inputPaths), "contains invalid path(s)");
File.WriteAllText(outputPath, string.Join(FileMergeDivider, inputPaths.Select(File.ReadAllText)));
}

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

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 ! ;)

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);
}
}

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

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", ""));
}

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');

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));

Fastest way to find strings in a file

I have a log file that is not more than 10KB (File size can go up to 2 MB max) and I want to find if atleast one group of these strings occurs in the files. These strings will be on different lines like,
ACTION:.......
INPUT:...........
RESULT:..........
I need to know atleast if one group of above exists in the file. And I have do this about 100 times for a test (each time log is different, so I have reload and read the log), so I am looking for fastest and bets way to do this.
I looked up in the forums for finding the fastest way, but I dont think my file is too big for those silutions.
Thansk for looking.

I would read it line by line and check the conditions. Once you have seen a group you can quit. This way you don't need to read the whole file into memory. Like this:
public bool ContainsGroup(string file)
{
using (var reader = new StreamReader(file))
{
var hasAction = false;
var hasInput = false;
var hasResult = false;
while (!reader.EndOfStream)
{
var line = reader.ReadLine();
if (!hasAction)
{
if (line.StartsWith("ACTION:"))
hasAction = true;
}
else if (!hasInput)
{
if (line.StartsWith("INPUT:"))
hasInput = true;
}
else if (!hasResult)
{
if (line.StartsWith("RESULT:"))
hasResult = true;
}
if (hasAction && hasInput && hasResult)
return true;
}
return false;
}
}
This code checks if there is a line starting with ACTION then one with INPUT and then one with RESULT. If the order of those is not important then you can omit the if () else if () checks. In case the line does not start with the strings replace StartsWith with Contains.

Here's one possible way to do it:
StreamReader sr;
string fileContents;
string[] logFiles = Directory.GetFiles(#"C:\Logs");
foreach (string file in logFiles)
{
using (StreamReader sr = new StreamReader(file))
{
fileContents = sr.ReadAllText();
if (fileContents.Contains("ACTION:") || fileContents.Contains("INPUT:") || fileContents.Contains("RESULT:"))
{
// Do what you need to here
}
}
}
You may need to do some variation based on your exact implementation needs - for example, what if the word spans two lines, does the line need to start with the word, etc.
Added
Alternate line-by-line check:
StreamReader sr;
string[] lines;
string[] logFiles = Directory.GetFiles(#"C:\Logs");
foreach (string file in logFiles)
{
using (StreamReader sr = new StreamReader(file)
{
lines = sr.ReadAllLines();
foreach (string line in lines)
{
if (line.Contains("ACTION:") || line.Contains("INPUT:") || line.Contains("RESULT:"))
{
// Do what you need to here
}
}
}
}

Take a look at How to Read Text From a File. You might also want to take a look at the String.Contains() method.
Basically you will loop through all the files. For each file read line-by-line and see if any of the lines contains 1 of your special "Sections".

You don't have much of a choice with text files when it comes to efficiency. The easiest way would definitely be to loop through each line of data. When you grab a line in a string, split it on the spaces. Then match those words to your words until you find a match. Then do whatever you need.
I don't know how to do it in c# but in vb it would be something like...
Dim yourString as string
Dim words as string()
Do While objReader.Peek() <> -1
yourString = objReader.ReadLine()
words = yourString.split(" ")
For Each word in words()
If Myword = word Then
do stuff
End If
Next
Loop
Hope that helps

This code sample searches for strings in a large text file. The words are contained in a HashSet. It writes the found lines in a temp file.
if (File.Exists(#"temp.txt")) File.Delete(#"temp.txt");
String line;
String oldLine = "";
using (var fs = File.OpenRead(largeFileName))
using (var sr = new StreamReader(fs, Encoding.UTF8, true))
{
HashSet<String> hash = new HashSet<String>();
hash.Add("house");
using (var sw = new StreamWriter(#"temp.txt"))
{
while ((line = sr.ReadLine()) != null)
{
foreach (String str in hash)
{
if (oldLine.Contains(str))
{
sw.WriteLine(oldLine);
// write the next line as well (optional)
sw.WriteLine(line + "\r\n");
}
}
oldLine = line;
}
}
}

Parsing individual lines in a robots.txt file with C#

Working on an application to parse robots.txt. I wrote myself a method that pulled the the file from a webserver, and threw the ouput into a textbox. I would like the output to display a single line of text for every line thats in the file, just as it would appear if you were looking at the robots.txt normally, however the ouput in my textbox is all of the lines of text without carriage returns or line breaks. So I thought I'd be crafty, make a string[] for all the lines, make a foreach loop and all would be well. Alas that did not work, so then I thought I would try System.Enviornment.Newline, still not working. Here's the code as it sounds now....how can I change this so I get all the individual lines of robots.txt as opposed to a bunch of text cobbled together?
public void getRobots()
{
WebClient wClient = new WebClient();
string url = String.Format("http://{0}/robots.txt", urlBox.Text);
try
{
Stream data = wClient.OpenRead(url);
StreamReader read = new StreamReader(data);
string[] lines = new string[] { read.ReadToEnd() };
foreach (string line in lines)
{
textBox1.AppendText(line + System.Environment.NewLine);
}
}
catch (WebException ex)
{
MessageBox.Show(ex.Message, null, MessageBoxButtons.OK);
}
}

You are reading the entire file into the first element of the lines array:
string[] lines = new string[] {read.ReadToEnd()};
So all your loop is doing is adding the whole contents of the file into the TextBox, followed by a newline character. Replace that line with these:
string content = read.ReadToEnd();
string[] lines = content.Split(new string[] { "\r\n", "\n" }, StringSplitOptions.None);
And see if that works.
Edit: an alternative and perhaps more efficient way, as per Fish's comment below about reading line by line—replace the code within the try block with this:
Stream data = wClient.OpenRead(url);
StreamReader read = new StreamReader(data);
while (read.Peek() >= 0)
{
textBox1.AppendText(read.ReadLine() + System.Environment.NewLine);
}

You need to make the textBox1 multiline. Then I think you can simply go
textBox1.Lines = lines;
but let me check that

Try
public void getRobots()
{
WebClient wClient = new WebClient();
string robotText;
string[] robotLines;
System.Text.StringBuilder robotStringBuilder;
robotText = wClient.DownloadString(String.Format("http://{0}/robots.txt", urlBox.Text));
robotLines = robotText.Split(Environment.NewLine);
robotStringBuilder = New StringBuilder();
foreach (string line in robotLines)
{
robotStringBuilder.Append(line);
robotStringBuilder.Append(Environment.NewLine);
}
textbox1.Text = robotStringBuilder.ToString();
}

Try using .Read() in a while loop instead of .ReadToEnd() - I think you're just getting the entire file as one line in your lines array. Debug and check the count of lines[] to verify this.
Edit: Here's a bit of sample code. Haven't tested it, but I think it should work OK;
Stream data = wClient.OpenRead(url);
StreamReader read = new StreamReader(data);
List<string> lines = new List<string>();
string nextLine = read.ReadLine();
while (nextLine != null)
{
lines.Add(nextLine);
nextLine = read.ReadLine();
}
textBox1.Lines = lines.ToArray();