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Reading from text file using StreamReader

I have a text file and I'm using a StreamReader for read the entire file to a String array (String[]). So I'm using the StreamReader.ReadToEnd().Split() method for this. But the text file can contain for example a full name (so words which I want to use as one String) so I wrote this file using '|' as separator but when I use StreamReader.ReadToEnd().Split('|') the String array contains elements like this "\r\nSomeString". I think it occurs when I'm using StreamWriter.WriteLine().
Is there a way I can handle this problem?

Can you try System.IO.File
example:
string text = System.IO.File.ReadAllText(#"C:\Users\Public\TestFolder\WriteText.txt");
// Display the file contents to the console. Variable text is a string.
System.Console.WriteLine("Contents of WriteText.txt = {0}", text);
// Example #2
// Read each line of the file into a string array. Each element
// of the array is one line of the file.
string[] lines = System.IO.File.ReadAllLines(#"C:\Users\Public\TestFolder\WriteLines2.txt");
// Display the file contents by using a foreach loop.
System.Console.WriteLine("Contents of WriteLines2.txt = ");
foreach (string line in lines)
{
// Use a tab to indent each line of the file.
Console.WriteLine("\t" + line);
}
foreach (string line in System.IO.File.ReadAllLines(#"C:\Users\Public\TestFolder\WriteLines2.txt"))
{
var myArray = line.Split('\t');
}

Is there any way to get first line (header) and last line of blg file similar like csv file

I am able to get first line (header) and last line of CSV file using below code,
string lines = File.ReadAllLines(#"C:\Files\test.csv");
string firstLine = lines.First();
string lastLine = lines.Last();
string result = firstLine + "\r\n" + lastLine;
File.WriteAlltext(#"C:\Files\test_Copy.csv", result);
Now I have a same requirement for performance counter (blg) file, but looks like File Readline is not working for blg file.
string line1 = File.ReadLines(#"C:\Files\BasicPerfCounters.blg").First();
The above code for reading first line of blg won't throw any exception, but output is not plain text,
Whereas, the first line read of csv output is plain text,
Note - One thing I can do that I can convert blg file to csv file using Relog.exe (https://blogs.technet.microsoft.com/askperf/2008/05/20/two-minute-drill-relog-exe/) and then I can easily read first line (header).
Is there any way to get first line (header) of blg file without convert it to csv?
Here is sample blg file, https://github.com/Microsoft/Tx/blob/master/Traces/BasicPerfCounters.blg

How to add text to the line that starts with "hello" in a file

I have a file that contains many lines. There is a line here looking like below:
hello jim jack nina richi sam
I need to add a specific text salmon in this line and change it to below (it could be added anywhere in this line -end -begining - in the middle -doesnt matter ):
hello jim jack nina richi sam salmon
I tried:
string path = #"C:\testFolder\newTestLog.txt";
StreamReader myReader = new StreamReader(path);
string[] allLines = File.ReadAllLines(path);
foreach (string element in allLines) {
if (element.StartsWith("hello"))
{
Console.WriteLine(element);
}
}
myReader.Close();
}
Using this I'm able to read the file line by line and add each line to an array and print that line if that starts with "hello", but I'm not sure how to add text to this line

You should use what Joel answered it's nicer but if you're having trouble implementing it try this. After adding the salmon to the lines that start with hello you can overwrite the txt file by using File.WriteAllLines
string filePath = #"C:\testFolder\newTestLog.txt";
string[] allLines = File.ReadAllLines(filePath);
for(int i = 0; i < allLines.Length; i++)
{
if (allLines[i].StartsWith("hello"))
{
allLines[i] += " salmon";
}
}
File.WriteAllLines(filePath, allLines);

Try this:
string path = #"C:\testFolder\newTestLog.txt";
var lines = File.ReadLines(path).Select(l => l + l.StartsWith("hello")?" salmon":"");
foreach (string line in lines)
Console.WriteLine(line);
Note that this still only writes the results to the Console, as your sample does. It's not clear what you really want to happen with the output.
If you want this saved to the original file, you've opened up a small can of worms. Think of all of the data in your file as if it's stored in one contiguous block1. If you append text to any line in the file, that text has nowhere to go but to overwrite the beginning of the next. As a practical matter, if you need to modify file, this often means either writing out a whole new file, and then deleting/renaming when done, or alternatively keeping the whole file in memory and writing it all from start to finish.
Using the 2nd approach, where we keep everything in memory, you can do this:
string path = #"C:\testFolder\newTestLog.txt";
var lines = File.ReadAllLines(path).Select(l => l + l.StartsWith("hello")?" salmon":"");
File.WriteAllLines(path, lines);
1 In fact, a file may be split into several fragments on the disk, but even so, each fragment is presented to your program as part of a single whole.

Alternative to File.AppendAllText for newline

I am trying to read characters from a file and then append them in another file after removing the comments (which are followed by semicolon).
sample data from parent file:
Name- Harly Brown ;Name is Harley Brown
Age- 20 ;Age is 20 years
Desired result:
Name- Harley Brown
Age- 20
I am trying the following code-
StreamReader infile = new StreamReader(floc + "G" + line + ".NC0");
while (infile.Peek() != -1)
{
letter = Convert.ToChar(infile.Read());
if (letter == ';')
{
infile.ReadLine();
}
else
{
System.IO.File.AppendAllText(path, Convert.ToString(letter));
}
}
But the output i am getting is-
Name- Harley Brown Age-20
Its because AppendAllText is not working for the newline. Is there any alternative?

Sure, why not use File.AppendAllLines. See documentation here.
Appends lines to a file, and then closes the file. If the specified file does not exist, this method creates a file, writes the specified lines to the file, and then closes the file.
It takes in any IEnumerable<string> and adds every line to the specified file. So it always adds the line on a new line.
Small example:
const string originalFile = #"D:\Temp\file.txt";
const string newFile = #"D:\Temp\newFile.txt";
// Retrieve all lines from the file.
string[] linesFromFile = File.ReadAllLines(originalFile);
List<string> linesToAppend = new List<string>();
foreach (string line in linesFromFile)
{
// 1. Split the line at the semicolon.
// 2. Take the first index, because the first part is your required result.
// 3. Trim the trailing and leading spaces.
string appendAbleLine = line.Split(';').FirstOrDefault().Trim();
// Add the line to the list of lines to append.
linesToAppend.Add(appendAbleLine);
}
// Append all lines to the file.
File.AppendAllLines(newFile, linesToAppend);
Output:
Name- Harley Brown
Age- 20
You could even change the foreach-loop into a LINQ-expression, if you prefer LINQ:
List<string> linesToAppend = linesFromFile.Select(line => line.Split(';').FirstOrDefault().Trim()).ToList();

Why use char by char comparison when .NET Framework is full of useful string manipulation functions?
Also, don't use a file write function multiple times when you can use it only one time, it's time and resources consuming!
StreamReader stream = new StreamReader("file1.txt");
string str = "";
while ((string line = infile.ReadLine()) != null) { // Get every line of the file.
line = line.Split(';')[0].Trim(); // Remove comment (right part of ;) and useless white characters.
str += line + "\n"; // Add it to our final file contents.
}
File.WriteAllText("file2.txt", str); // Write it to the new file.

You could do this with LINQ, System.File.ReadLines(string), and System.File.WriteAllLines(string, IEnumerable<string>). You could also use System.File.AppendAllLines(string, IEnumerable<string>) in a find-and-replace fashion if that was, in fact, the functionality you were going for. The difference, as the names suggest, is whether it writes everything out as a new file or if it just appends to an existing one.
System.IO.File.WriteAllLines(newPath, System.IO.File.ReadLines(oldPath).Select(c =>
{
int semicolon = c.IndexOf(';');
if (semicolon > -1)
return c.Remove(semicolon);
else
return c;
}));
In case you aren't super familiar with LINQ syntax, the idea here is to loop through each line in the file, and if it contains a semicolon (that is, IndexOf returns something that is over -1) we cut that off, and otherwise, we just return the string. Then we write all of those to the file. The StreamReader equivalent to this would be:
using (StreamReader reader = new StreamReader(oldPath))
using (StreamWriter writer = new StreamWriter(newPath))
{
string line;
while ((line = reader.ReadLine()) != null)
{
int semicolon = line.IndexOf(';');
if (semicolon > -1)
line = c.Remove(semicolon);
writer.WriteLine(line);
}
}
Although, of course, this would feed an extra empty line at the end and the LINQ version wouldn't (as far as I know, it occurs to me that I'm not one hundred percent sure on that, but if someone reading this does know I would appreciate a comment).
Another important thing to note, just looking at your original file, you might want to add in some Trim calls, since it looks like you can have spaces before your semicolons, and I don't imagine you want those copied through.

how to replace a character in a string and save into text file in c#

I'm trying to replace pipe symbol(|) with new line(\n) in my text(test1.txt) file. But when I'm trying to save it in text(test2.text) file the result is not coming in my test2.txt file but I see the result in my console window. Any one please help on this.
string lines = File.ReadAllText(#"C:\NetProject\Nag Assignments\hi.txt");
//string input = "abcd|efghijk|lmnopqrstuvwxyz";
lines = lines.Replace('|', '\n');
File.WriteAllText(#"C:\NetProject\Nag Assignments\hi2.txt", lines);
Console.WriteLine(lines);

You can try this one:
lines = lines.Replace("|", Environment.NewLine);
It returns "\r\n", for non-Unix platforms according to documentation.

Seems like you want multiple things here. (both original question and subsequent comments)
One is to separate the lines and be able to reference them separately:
string[] separatedLines = lines.Split('|');
The other is to join them back together with a different separator:
string rejoinedLines = string.Join(Environment.NewLine, separatedLines);
You then have access to the individual lines from the separatedLines variable above such as separatedLines[0] and you can also write the rejoinedLines variable back to the other file like you wanted.
EDIT: For example, the following code:
string lines = "a|bc|def";
string[] separatedLines = lines.Split('|');
string rejoinedLines = string.Join(Environment.NewLine, separatedLines);
for (int i = 0; i < separatedLines.Length; i++)
{
Console.WriteLine("Line {0}: {1}", i + 1, separatedLines[i]);
}
Gives output of:
Line 1: a
Line 2: bc
Line 3: def

Instead of:
lines = lines.Replace('|', '\n');
Try:
lines = lines.Replace("|","\r\n");

string[] space = lines.Split ('|');
Will save every substring in space.
The line break should be \r\n for carriage return. It depends if you are reading a file binary or text mode. \n is used in text mode while \r\n is used in binary mode.