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How to remove texts after a character?

I have an array that holds user and passwords in user:pass form, and I like ro remove lines which pass is less than 8 characters or password uses repetitive chars like 111111,22222222222,...
I have tried string.take but it takes lines completely, I need conditional deletion.
public string[] lines;
//open file dialogue to load the user pass file
lines = File.ReadAllLines(openFileDialog1.FileName);
//delete button click event
//the place that I have problem
I have email:pass combination like so:
email1:1234567895121
email2:12345
email4:11111
email5"454545454545
and I would like the output to be like
email1:1234567895121
email5"454545454545

Just loop the characters of every line and see if the current is equal to the previous:
public string[] lines = File.ReadAllLines(openFileDialog1.FileName);
var filteredLines = new List<string>(lines);
foreach(var line in lines)
{
var pair = line.Split(':');
var mail = pair[0];
var pass = pair[1]; // may throw exception on invalid format of your line
for(int i = 1; i < pass.Length; i++)
{
if(pass[i] == pass[i - 1])
{
filteredLines.Remove(line);
break; // will break inner loop and continue on next line
}
}
}

string[] lines =
{
"email1:1234567895121",
"email2:12345",
"email3:22222222222",
"email4:11111",
"email5:454545454545"
};
lines = lines
.Where(s =>
{
string pass = s.Split(new[] { ':' }, 2)[1];
return pass.Length >= 8 && pass.Any(c => c != pass[0]);
})
.ToArray();
foreach (var s in lines)
Console.WriteLine(s);
Output:
email1:1234567895121
email5:454545454545

problem reading .txt file in C# starting from (after immediate empty whole line) to (the next empty whole line)

I am trying to randomly read a huge .txt file. It has tons of paragraphs separated by a full line of empty space prior and post each paragraph. I would like each time I randomly read that it pulls up a full intact paragraph without any characters or words missing for the sake of context. I appreciated the help in advance.
I added a for loop just to test it out and see if I can at some point include a way to recognize consecutively running empty space. That would only work post already selected the starting point obviously if applied.
public static string GetRandomLine(string filename)
{
var lines = File.ReadAllLines(filename);
var lineNumber = _rand.Next(0, lines.Length);
string reply = lines[lineNumber];
return reply ;
}

Try the following:
public static string[] GetRandomParagraph(string filePath)
{
if (File.Exists(filePath))
{
string text = File.ReadAllText(filePath);
string[] paragraphs = text.Split(new string[] { "\n\n" }, StringSplitOptions.None);
return paragraphs[new Random().Next(0, paragraphs.Length)].Split('\n');
}
else
throw new FileNotFoundException("The file was not found", filePath);
}
I really hope that is that what you are looking for.

// This builds a list of Paragraph first
public static List<string> GetParagraphs(string filename)
{
var paragraphs = new List<string>();
var lines = File.ReadAllLines(filename);
bool newParagraph = true;
string CurrentParagraph = string.Empty;
// Build the list of paragraphs by adding to the currentParagraph until empty lines and then starting a new one
foreach(var line in lines)
{
if(newParagraph)
{
CurrentParagraph = line;
newParagraph = false;
}
else
{
if(string.IsNullOrWhiteSpace(line))// we're starting a new paragraph, add it to the list of paragraphs and reset current paragraph for next one
{
paragraphs.Add(CurrentParagraph);
CurrentParagraph = string.Empty;
newParagraph = true;
}
else // we're still in the same paragraph, add the line to current paragraph
{
newParagraph += (Environment.NewLine + line);
}
}
}
// Careful, if your file doesn't end with a newline the last paragraph won't count as one, in that case add it manually here.
}
public static Random rnd = new Random();
// And this returns a random one
public static string GetRandomParagraph(string fileName)
{
var allParagraphs = GetParagraphs(filename);
allParagraphs[rnd.Next(0,allParagraphs.length-1)]; // pick one of the paragraphs at random, stop at length-1 as collection indexers are 0 based
}
Note that if you're always reading from the same file this could be much faster by only calling GetParagraphs once and keeping the list of paragraphs in memory.

Try this:
public static string GetRandomLine(string filename)
{
var lines = File.ReadAllLines(filename);
var lineNumber = _rand.Next(0, lines.Length - 1);
var blankBefore = lineNumber;
var blankAfter = lineNumber + 1;
string reply = "";
while (lines[blankBefore].Length > 0)
{
blankBefore--;
}
while (lines[blankAfter].Length != 0)
{
blankAfter++;
}
for ( int i = blankBefore + 1; blankBefore < blankAfter; blankBefore++)
{
reply += lines[i];
}
return reply;
}
Based on your description, I'm assuming the file begins and ends with a blank line. By setting the exclusive upper bound of the random line to be one less than the length of lines, you avoid the chance of the random line being the last line of the file. If the random line is a blank line, blankBefore will be the index of that line, otherwise, it will be back tracked until it reaches the previous blank. blankAfter starts as the index of the next line after the random line and if that line is not blank, blankAfter is increased until it is the index of the next blank line.
Once you have the index of the blank lines before and after the target paragraph, simply append the lines between them to reply.
If the first and last lines of the file are not blank, you would need to verify that blankBefore and blankAfter remain within the bounds of the array.

I made some modifications to the code provided above by #TheCoderCrab. I turned the method to a string method so it would return a string. I simply added a for loop append all the characters of the paragraph array on to a new string which returns it to the main. Thank you.
public static string GetRandomParagraph(string filePath)
{
if (File.Exists(filePath))
{
string text = File.ReadAllText(filePath);
string[] paragraphs = text.Split(new string[] { "\n\n" }, StringSplitOptions.None);
string [] paragraph = paragraphs[new Random().Next(0, paragraphs.Length)].Split('\n');
//Added a for loop to build the string out of all the characters in the 'paragraph' array index.
string pReturn = "";
for (int a = 0; a < paragraph.Length; a++)
{
//Loop through and consecutively append each character of mapped array index to a return string 'pReturn'
pReturn = pReturn + paragraph[a].ToString();
}
return pReturn;
}
else
throw new FileNotFoundException("The file was not found", filePath);
}

To get intact paragraphs
public static string GetRandomParagraph(string fileName)
{
/*
Rather than reading all the lines, read all the text
this gives you the ability to split by paragraph
*/
var allText = File.ReadAllText(fileName);
// Use as separator for paragraphs
var paragraphSeparator = $"{Environment.NewLine}{Environment.NewLine}";
// Treat large white spaces after a new line as separate paragraphs
allText = Regex.Replace(allText, #"(\n\s{3,})", paragraphSeparator);
// Split the text into paragraphs
var paragraphs = allText.Split(paragraphSeparator);
// Get a random index between 0 and the amount of paragraphs
var randomParagraph = new Random().Next(0, paragraphs.Length);
return paragraphs[randomParagraph];
}

removing additional space above last line text in textfile c#

The following code is used by me to convert the entries in a datagrid view into a text file! (The process of creating a text file is successfull) After converting the datagrid view entries into a string I append a string from outside(This should appear on the last line of the textfile)
private void button1_Click_1(object sender, EventArgs e) // converting data grid value to single string
{
StringBuilder file = new StringBuilder();
for (int i = 0; i < dataGridView2.Rows.Count; i++)
{
for (int j = 0; j < dataGridView2.Rows[i].Cells.Count; j++)
{
var val = dataGridView2.Rows[i].Cells[j].Value;
if (val == null)
continue;//IF NULL GO TO NEXT CELL, MAYBE YOU WANT TO PUT EMPTY SPACE
var s = val.ToString();
file.Append(s.Replace(Environment.NewLine, " "));
}
file.AppendLine(); // NEXT ROW WILL COME INTO NEXT LINE
}
file.Append("Hello");
using (StreamWriter sw = new
StreamWriter(#"C:\Users\sachinthad\Desktop\VS\Tfiles\file.txt"))
{
sw.Write(x);
}
}
But when I check text file the outside string("Hello" in this scenario) appears on the last line but there is an additional space above it! How can i remove this additional space?

You can use string.Joinwhich concatenates a collection of strings with a separator in between. Together with refactoring it to use linq .Select:
var lines = dataGridView2.Rows.Select(row => string.Join(" ",
row.Cells.Select(cell => cell.Value).Where(val => val != null));
Then of course you can also use it on the entire collection of lines to concatenate them with a new line:
// Will eliminate problem of extra \n at the end
var result = string.Join(Environment.NewLine, lines);
If you prefer having the loops instead of linq then what you can do in the inner loop is add the values to a List<string> initialized in the outer loop. After the inner loop ends to use string.Join on the values of that list. Psudocode:
for each row:
List<string> items = new List<string>();
for each column in row:
items.Add(value of column);
file.Append(string.Join(" ", items));

Change a text in files in a folder next to string "Text_ID"

  Example of a text file below 
text_file a
Text_ID "441124_aad0656_1234"
Text_FILE_NAME
I would like to keep only last index of string "1234"
StreamReader streamReader = new StreamReader(text);
string text2;
while ((text2 = streamReader.ReadLine()) != null)
{
num++;
string[] array3 = text2.Split(new char[0]);
if (array3[0] == "Text_ID")
{
string[] array4 = array3[1].Split(new char[] {'_'});
string value = "Text_ID" + " " + '"' + array4[1];
streamWriter.WriteLine(value);
}
else
{
streamWriter.WriteLine(text2);
}
}

try below code, and hope it should work for you.
var startsWith = "Text_ID";
var allLines = File.ReadAllLines("a.txt").ToList();
allLines = allLines.Select(ln =>
{
if(ln.StartsWith(startsWith))
{
var finalValue = ln.Split(' ')[1].Trim('"').Split('_').Last();
//get update line
return string.Format("{0} \"{1}\"", startsWith, finalValue);
}
return ln;
}).ToList();
//Write back to file.
File.WriteAllLines("a.txt", allLines.ToArray());
Content before code execution.
Record 1
Text_ID "441124_aad0656_1234"
other content.
Record 2
Text_ID "Deepak_Sharma"
other content for line 2
Content in file after execution.
Record 1
Text_ID "1234"
other content.
Record 2
Text_ID "Sharma"
other content for line 2

You could use File.ReadAllLines to read the file into an array, then search through the array for the line you want to change, replace that line with the new string, and then use File.WriteAllLines to write the array back to the file:
var filePath = #"f:\public\temp\temp.txt";
// The string to search for
var searchTxt = "Text_ID";
// Read all the lines of the file into an array
var fileLines = File.ReadAllLines(filePath);
// Loop through each line in the array
for(int i = 0; i < fileLines.Length; i++)
{
// Check if the line begins with our search term
if (fileLines[i].Trim().StartsWith(searchTxt, StringComparison.OrdinalIgnoreCase))
{
// Get the end of the line, after the last underscore
var lastPartOfLine = fileLines[i].Substring(fileLines[i].LastIndexOf("_") + 1);
// Combine our search string, a quote, and the end of the line
fileLines[i] = $"{searchTxt} \"{lastPartOfLine}";
// We found what we were looking for, so we can exit the for loop now
// Remove this line if you expect to find more than one match
break;
}
}
// Write the lines back to the file
File.WriteAllLines(filePath, fileLines);
If you only want to save the last four lines of the file, you can call Skip and pass in the Length of the array minus the number of lines you want to keep. This skips all the entries up to the number that you want to save:
// Read all the lines of the file into an array
var fileLines = File.ReadAllLines(filePath);
// Take only the last 4 lines
fileLines = fileLines.Skip(fileLines.Length - 4).ToArray();

how I can copy the text in a specified field, without mention the line number

I have the next code :
private void button1_Click_1(object sender, EventArgs e)
{
string path = AppDomain.CurrentDomain.BaseDirectory.ToString();
var link = File.ReadLines(path + "test.txt").ToArray();
var lines = File.ReadAllLines(path + "test2.txt");
foreach (var txt in link )
{
if (txt.Contains("Output="))
{
var outputPath = txt.Split('=')[1];
if (File.Exists(path + "test2.txt"))
{
var modifiedLines = lines.Select(line =>
{
if (line.StartsWith("outlog=\""))
{
return string.Format("outlog=\"{0}\"", outputPath);
}
else
{
return line;
}
});
File.WriteAllLines(path+ "test2.txt", modifiedLines);
}
}
}
With this code I whan to copy what is after equel from Output="C:\temp\out.log"(who is in test.txt), after equal in outlog=(who is in test2.txt).
How I can copy the text who exists in one text file test.txt, in a specified location from a second field test2.txt, without mentioned the line number ?
Here I put just a row, but in my files text I have many rows, but I think I make this to work, I handle with another rows.
test.txt have
Licfile="C:\temp\lic.lic"
Output="C:\temp\out.log"
Title="name"
test2.txt have
outlog=
license=
lmgr_files=
license_path=
and after runing the code the test2.txt I want to looks like this:
outlog="C:\temp\out.log"
license_path="C:\temp\lic.lic"
lmgr_files=false
license=true

I am confused about your problem but i just want to try to give you an opinion. I hope it may be help you. But line numbers are really important for these problem.
String[] arrayOld = File.ReadAllLines(#"C:\test.txt");
String[] arrayNew = new string[arrayOld.Length];
if (arrayOld[0].Contains("Licfile=")) // If statements could be more
{
Array.Copy(arrayOld,0,arrayNew,0,2); // How many line will add
}
for (int i = 0; i < 2; i++)
{
File.AppendAllText(#"D:\test2.txt", arrayNew[i] + Environment.NewLine); // It'll add all lines
}
P.S.: Don't forget to add strings like lineOne = "outlog=" + locString; etc.