Develop Reference

C# Regular expression To replace all matches in the string

I Have one text file and I want to replaces all matches in each line, so I defined Pattern and I loop through to the text file after I want to write the result in another file, unfortunately my pattern is only replace first occurrence of the word what did |I do in a wrong way?
Content of text file:
"testebook kok o testebook\ntestbbb1232 joj ds testbbb1232"
using System.Text.RegularExpressions;
string filePath = "test.txt";
string fileNewPath = "test1.txt";
string ma = #"^test[0-9a-zA-Z]+";
string newString = string.Empty;
using(StreamReader sr = new(filePath)){
string line = sr.ReadLine();
while (line != null){
while(Regex.IsMatch(line, ma) != false){
line = Regex.Replace(line, ma, "");
}
newString += line + "\n";
line = sr.ReadLine();
}
}
using(StreamWriter sw = new(fileNewPath)){
sw.WriteLine(newString);
}

Your code is correct but your regex pattern is not correct.
you should write this:
string ma = #"test[0-9a-zA-Z]+";
The letter "^" has removed from pattern

So I modified My pattern and remove start with character and everything works now as desired
using System.Text.RegularExpressions;
string filePath = "test.txt";
string fileNewPath = "test1.txt";
MatchesFinder test = new(filePath, fileNewPath);
test.RunTheProcess();
class MatchesFinder{
private string filePath;
private string fileNewPath;
private string ma = #"test[a-zA-Z0-9]+";
public MatchesFinder(string filePath,string fileNewPath){
this.filePath = filePath;
this.fileNewPath = fileNewPath;
}
public void RunTheProcess(){
string newString = string.Empty;
using(StreamReader sr = new(filePath)){
string line = sr.ReadLine();
while (line != null){
while(Regex.IsMatch(line, ma) != false){
line = Regex.Replace(line, ma, string.Empty);
}
newString += line.TrimStart() + "\n";
line = sr.ReadLine();
}
}
using(StreamWriter sw = new(fileNewPath)){
sw.WriteLine(newString);
}
}
}

I think you don´t need to check IsMatch separately, just calling Regex.Replace should yield the same result.
Also, newString += line.TrimStart() + "\n"; means you´re copying all the lines you´ve already checked every time you append a new line. I´d either write directly to the output stream or at least use a StringBuilder if you really want to have the full file in memory for some reason.
Something like this:
using var sw = new StreamWriter(fileNewPath);
using var sr = new StreamReader(filePath);
var line = sr.ReadLine();
while (line != null){
line = Regex.Replace(line, ma, string.Empty);
sw.WriteLine(line.TrimStart());
line = sr.ReadLine();
}

C# Replace the end of a string starting from the position of a match

I have a string (from a filename) like this: Mytext_edit1345.jpg
I just want to cut the "_edit1345" so I can get Mytext.jpg as a result.
Is Regex.Replace the best way to go for me?
string result = Regex.Replace(Bildname, pattern, "");
What pattern do i need?

You can use the Path class and string methods like String.Remove
string fileNameWOE = Path.GetFileNameWithoutExtension(fileName);
int indexOfUnderscore = fileNameWOE.IndexOf('_');
if(indexOfUnderscore >= 0)
fileNameWOE = fileNameWOE.Remove(indexOfUnderscore);
fileName = fileNameWOE + Path.GetExtension(fileName);

Use String.Substring with Path.GetExtension like:
string fileName = "Mytext_edit1345.jpg";
string newFileName = fileName;
if (fileName.Contains('_'))
{
newFileName = fileName.Substring(0, fileName.IndexOf('_')) +
Path.GetExtension(fileName);
}

Use the below pattern to match the substring(from_ upto the next .) you want to cut-down,
_[^.]*
DEMO
Your code would be,
string str = "Mytext_edit1345.jpg";
string result = Regex.Replace(str, #"_[^.]*", "");
Console.WriteLine(result);
Console.ReadLine();
IDEONE

error : The given path's format is not supported

Getting this error The given path's format is not supported. at this line
System.IO.Directory.CreateDirectory(visit_Path);
Where I am doing mistake in below code
void Create_VisitDateFolder()
{
this.pid = Convert.ToInt32(db.GetPatientID(cmbPatientName.SelectedItem.ToString()));
String strpath = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
String path = strpath + "\\Patients\\Patient_" + pid + "\\";
string visitdate = db.GetPatient_visitDate(pid);
this.visitNo = db.GetPatientID_visitNo(pid);
string visit_Path = path +"visit_" + visitNo + "_" + visitdate+"\\";
bool IsVisitExist = System.IO.Directory.Exists(path);
bool IsVisitPath=System.IO.Directory.Exists(visit_Path);
if (!IsVisitExist)
{
System.IO.Directory.CreateDirectory(path);
}
if (!IsVisitPath)
{
System.IO.Directory.CreateDirectory(visit_Path);\\error here
}
}
getting this value for visit_Path
C:\Users\Monika\Documents\Visual Studio 2010\Projects\SonoRepo\SonoRepo\bin\Debug\Patients\Patient_16\visit_4_16-10-2013 00:00:00\

You can not have : in directory name, I suggest you to use this to string to get date in directory name:
DateTime.Now.ToString("yyyy-MM-dd hh_mm_ss");
it will create timestamp like:
2013-10-17 05_41_05
additional note:
use Path.Combine to make full path, like:
var path = Path.Combine(strpath , "Patients", "Patient_" + pid);
and last
string suffix = "visit_"+visitNo+"_" + visitdate;
var visit_Path = Path.Combine(path, suffix);

In general always use Path.Combine to create paths:
String strPath = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
String path = Path.Combine(strPath,"Patients","Patient_" + pid);
string visitdate = db.GetPatient_visitDate(pid);
this.visitNo = db.GetPatientID_visitNo(pid);
string fileName = string.Format("visit_{0}_{1}", visitNo, visitdate);
string visit_Path = Path.Combine(path, fileName);
bool IsVisitExist = System.IO.Directory.Exists(path);
bool IsVisitPath=System.IO.Directory.Exists(visit_Path);
To replace invalid characters from a filename you could use this loop:
string invalidChars = new string(Path.GetInvalidFileNameChars()) + new string(Path.GetInvalidPathChars());
foreach (char c in invalidChars)
{
visit_Path = visit_Path.Replace(c.ToString(), ""); // or with "."
}

You can't have colons : in file paths

You can't use colons (:) in a path. You can for example Replace() them with dots (.).

Just wanted to add my two cents.
I assigned the path from a text box to string and also adding additional strings, but I forgot to add the .Text to the text box variable.
So instead of
strFinalPath = TextBox1.Text + strIntermediatePath + strFilename
I wrote
strFinalPath = TextBox1 + strIntermediatePath + strFilename
So the path became invalid because it contained invalid characters.
I was surprised that c# instead of rejecting the assignment because of type mismatch, assigned invalid value to the final string.
So look at the path assignment string closely.

How to trim/replace a char '\' or '"' from a string?

I need to use a string for path for a file but sometimes there are forbidden characters in this string and I must replace them. For example, my string _title is rumbaton jonathan \"racko\" contreras.
Well I should replace the chars \ and ".
I tried this but it doesn't work:
_title.Replace(#"/", "");
_title.Replace(#"\", "");
_title.Replace(#"*", "");
_title.Replace(#"?", "");
_title.Replace(#"<", "");
_title.Replace(#">", "");
_title.Replace(#"|", "");

Since strings are immutable, the Replace method returns a new string, it doesn't modify the instance you are calling it on. So try this:
_title = _title
.Replace(#"/", "")
.Replace(#"""", "")
.Replace(#"*", "")
.Replace(#"?", "")
.Replace(#"<", "")
.Replace(#">", "")
.Replace(#"|", "");
Also if you want to replace " make sure you have properly escaped it.

Try regex
string illegal = "\"M\"\\a/ry/ h**ad:>> a\\/:*?\"| li*tt|le|| la\"mb.?";
string regexSearch = new string(Path.GetInvalidFileNameChars()) + new string(Path.GetInvalidPathChars());
Regex r = new Regex(string.Format("[{0}]", Regex.Escape(regexSearch)));
illegal = r.Replace(illegal, "");
Before: "M"\a/ry/ h**ad:>> a/:?"| litt|le|| la"mb.?
After: Mary had a little lamb.
Also another answer from same post is much cleaner
private static string CleanFileName(string fileName)
{
return Path.GetInvalidFileNameChars().Aggregate(fileName, (current, c) => current.Replace(c.ToString(), string.Empty));
}
from How to remove illegal characters from path and filenames?

Or you could try this (probably terribly inefficient) method:
string inputString = #"File ~!##$%^&*()_+|`1234567890-=\[];',./{}:""<>? name";
var badchars = Path.GetInvalidFileNameChars();
foreach (var c in badchars)
inputString = inputString.Replace(c.ToString(), "");
The result will be:
File ~!##$%^&()_+`1234567890-=[];',.{} name
But feel free to add more chars to the badchars before running the foreach loop on them.

See http://msdn.microsoft.com/cs-cz/library/fk49wtc1.aspx:
Returns a string that is equivalent to the current string except that all instances of oldValue are replaced with newValue.

I have written a method to do the exact operation that you want and with much cleaner code.
The method
public static string Delete(this string target, string samples) {
if (string.IsNullOrEmpty(target) || string.IsNullOrEmpty(samples))
return target;
var tar = target.ToCharArray();
const char deletechar = '♣'; //a char that most likely never to be used in the input
for (var i = 0; i < tar.Length; i++) {
for (var j = 0; j < samples.Length; j++) {
if (tar[i] == samples[j]) {
tar[i] = deletechar;
break;
}
}
}
return tar.ConvertToString().Replace(deletechar.ToString(CultureInfo.InvariantCulture), string.Empty);
}
Sample
var input = "rumbaton jonathan \"racko\" contreras";
var cleaned = input.Delete("\"\\/*?><|");
Will result in:
rumbaton jonathan racko contreras

Ok ! I've solved my issue thanks to all your indications. This is my correction :
string newFileName = _artist + " - " + _title;
char[] invalidFileChars = Path.GetInvalidFileNameChars();
char[] invalidPathChars = Path.GetInvalidPathChars();
foreach (char invalidChar in invalidFileChars)
{
newFileName = newFileName.Replace(invalidChar.ToString(), string.Empty);
}
foreach (char invalidChar in invalidPathChars)
{
newFilePath = newFilePath.Replace(invalidChar.ToString(), string.Empty);
}
Thank you so musch everybody :)

Trouble passing a parameter to a class in C#

I'm having a bit of trouble passing this parameter to a class i have. Does anybody have any ideas?
Class 1's code:
public void DriveRecursion(string retPath)
{
//recurse through files. Let user press 'ok' to move onto next step
// string[] files = Directory.GetFiles(retPath, "*.*", SearchOption.AllDirectories);
string pattern = " *[\\~#%&*{}/<>?|\"-]+ *";
//string replacement = "";
Regex regEx = new Regex(pattern);
string[] fileDrive = Directory.GetFiles(retPath, "*.*", SearchOption.AllDirectories);
List<string> filePath = new List<string>();
dataGridView1.Rows.Clear();
try
{
foreach (string fileNames in fileDrive)
{
if (regEx.IsMatch(fileNames))
{
string fileNameOnly = Path.GetFileName(fileNames);
string pathOnly = Path.GetDirectoryName(fileNames);
DataGridViewRow dgr = new DataGridViewRow();
filePath.Add(fileNames);
dgr.CreateCells(dataGridView1);
dgr.Cells[0].Value = pathOnly;
dgr.Cells[1].Value = fileNameOnly;
dataGridView1.Rows.Add(dgr);
\\I want to pass fileNames to my FileCleanup Method
\\I tried this:
\\SanitizeFileNames sf = new SanitizeFileNames();
\\sf.Add(fileNames); <-- this always gets an error..plus it is not an action i could find in intellisense
}
else
{
continue;
}
}
}
catch (Exception e)
{
StreamWriter sw = new StreamWriter(retPath + "ErrorLog.txt");
sw.Write(e);
}
}
Class 2's code:
public class SanitizeFileNames
{
public void FileCleanup(string fileNames)
{
string regPattern = " *[\\~#%&*{}/<>?|\"-]+ *";
string replacement = "";
Regex regExPattern = new Regex(regPattern);
}
What i want to do in SanitizeFileNames is do a foreach through the FileNames & FilePath and replace invalid chars (as defined in my Regex pattern). So, something along the lines of this:
using (StreamWriter sw = new StreamWriter(#"S:\File_Renames.txt"))
{
//Sanitize and remove invalid chars
foreach (string Files2 in filePath)
{
try
{
string filenameOnly = Path.GetFileName(Files2);
string pathOnly = Path.GetDirectoryName(Files2);
string sanitizedFilename = regEx.Replace(filenameOnly, replacement);
string sanitized = Path.Combine(pathOnly, sanitizedFilename);
sw.Write(sanitized + "\r\n");
System.IO.File.Move(Files2, sanitized);
}
//error logging
catch(Exception ex)
{
StreamWriter sw2 = new StreamWriter(#"S:\Error_Log.txt");
sw2.Write("ERROR LOG");
sw2.WriteLine(DateTime.Now.ToString() + ex + "\r\n");
sw2.Flush();
sw2.Close();
}
}
}
However, I'm having trouble passing the fileNames into my SanitizeFileNames class. Can anybody help me?

dataGridView1.Rows.Clear();
try
{
foreach (string fileNames in fileDrive)
{
if (regEx.IsMatch(fileNames))
{
string fileNameOnly = Path.GetFileName(fileNames);
string pathOnly = Path.GetDirectoryName(fileNames);
DataGridViewRow dgr = new DataGridViewRow();
filePath.Add(fileNames);
dgr.CreateCells(dataGridView1);
dgr.Cells[0].Value = pathOnly;
dgr.Cells[1].Value = fileNameOnly;
dataGridView1.Rows.Add(dgr);
new SanitizeFileNames().FileCleanup(fileNames);
}
else
{
continue;
}
}
}

I suppose you want to pass a dirty name to the FileCleanup function and get a clean out. Here is how you can do that :
public String FileCleanup(string fileNames)
{
string regPattern = " *[\\~#%&*{}/<>?|\"-]+ *";
string replacement = "";
Regex regExPattern = new Regex(regPattern);
...
return cleanName;
}
and use it in your code like this:
String cleanName = new SanitizeFileNames().FileCleanup(fileNames);
where you put the comment.

You can create a third class static class and add static variable called files “public static List<string> Files= new List<string>()” as example.
When you create the files add the same files to the static variable.
When you clean the files loop throw the static variable, and at the end clear it.

The parameter type should be an enumerable collection of some sort: a list or an array would do. Also, strings are immutable so you could return a list of cleaned up filenames:
public class SanitizeFilenames
{
public List<string> FileCleanUp(IEnumerable<string> filenames)
{
var cleanedFileNames = new List<string>();
var invalidChars = Path.GetInvalidFileNameChars();
foreach(string file in filenames)
{
if(file.IndexOfAny(invalidChars) != -1)
{
// clean the file name and add it to the cleanedFileNames list
}
else
{
// nothing to clean here
cleanedFileNames.Add(file);
}
}
return cleanedFileNames;
}
}