Replace Line Breaks in a String C#

The solutions posted so far either only replace Environment.NewLine or they fail if the replacement string contains line breaks because they call string.Replace multiple times.

Here's a solution that uses a regular expression to make all three replacements in just one pass over the string. This means that the replacement string can safely contain line breaks.

string result = Regex.Replace(input, @"\r\n?|\n", replacementString);

To extend The.Anyi.9's answer, you should also be aware of the different types of line break in general use. Dependent on where your file originated, you may want to look at making sure you catch all the alternatives...

string replaceWith = "";
string removedBreaks = Line.Replace("\r\n", replaceWith).Replace("\n", replaceWith).Replace("\r", replaceWith);

should get you going...

I would use Environment.Newline when I wanted to insert a newline for a string, but not to remove all newlines from a string.

Depending on your platform you can have different types of newlines, but even inside the same platform often different types of newlines are used. In particular when dealing with file formats and protocols.

string ReplaceNewlines(string blockOfText, string replaceWith)
{
    return blockOfText.Replace("\r\n", replaceWith).Replace("\n", replaceWith).Replace("\r", replaceWith);
}

Use new in .NET 6 method

myString = myString.ReplaceLineEndings();

Replaces ALL newline sequences in the current string.

Documentation: ReplaceLineEndings

If your code is supposed to run in different environments, I would consider using the Environment.NewLine constant, since it is specifically the newline used in the specific environment.

line = line.Replace(Environment.NewLine, "newLineReplacement");

However, if you get the text from a file originating on another system, this might not be the correct answer, and you should replace with whatever newline constant is used on the other system. It will typically be \n or \r\n.

if you want to "clean" the new lines, flamebaud comment using regex @"[\r\n]+" is the best choice.

using System;
using System.Text.RegularExpressions;

class MainClass {
  public static void Main (string[] args) {
    string str = "AAA\r\nBBB\r\n\r\n\r\nCCC\r\r\rDDD\n\n\nEEE";

    Console.WriteLine (str.Replace(System.Environment.NewLine, "-"));
    /* Result:
    AAA
    -BBB
    -
    -
    -CCC


    DDD---EEE
    */
    Console.WriteLine (Regex.Replace(str, @"\r\n?|\n", "-"));
    // Result:
    // AAA-BBB---CCC---DDD---EEE

    Console.WriteLine (Regex.Replace(str, @"[\r\n]+", "-"));
    // Result:
    // AAA-BBB-CCC-DDD-EEE
  }
}

To make sure all possible ways of line breaks (Windows, Mac and Unix) are replaced you should use:

string.Replace("\r\n", "\n").Replace('\r', '\n').Replace('\n', 'replacement');

and in this order, to not to make extra line breaks, when you find some combination of line ending chars.

Don't forget that replace doesn't do the replacement in the string, but returns a new string with the characters replaced. The following will remove line breaks (not replace them). I'd use @Brian R. Bondy's method if replacing them with something else, perhaps wrapped as an extension method. Remember to check for null values first before calling Replace or the extension methods provided.

string line = ...

line = line.Replace( "\r", "").Replace( "\n", "" );

As extension methods:

public static class StringExtensions
{
   public static string RemoveLineBreaks( this string lines )
   {
      return lines.Replace( "\r", "").Replace( "\n", "" );
   }

   public static string ReplaceLineBreaks( this string lines, string replacement )
   {
      return lines.Replace( "\r\n", replacement )
                  .Replace( "\r", replacement )
                  .Replace( "\n", replacement );
   }
}

Why not both?

string ReplacementString = "";

Regex.Replace(strin.Replace(System.Environment.NewLine, ReplacementString), @"(\r\n?|\n)", ReplacementString);

Note: Replace strin with the name of your input string.

I needed to replace the \r\n with an actual carriage return and line feed and replace \t with an actual tab. So I came up with the following:

public string Transform(string data)
{
    string result = data;
    char cr = (char)13;
    char lf = (char)10;
    char tab = (char)9;

    result = result.Replace("\\r", cr.ToString());
    result = result.Replace("\\n", lf.ToString());
    result = result.Replace("\\t", tab.ToString());

    return result;
}

var answer = Regex.Replace(value, "(\n|\r)+", replacementString);

As new line can be delimited by \n, \r and \r\n, first we’ll replace \r and \r\n with \n, and only then split data string.

The following lines should go to the parseCSV method:

function parseCSV(data) {
    //alert(data);
    //replace UNIX new lines
    data = data.replace(/\r\n/g, "\n");
    //replace MAC new lines
    data = data.replace(/\r/g, "\n");
    //split into rows
    var rows = data.split("\n");
}

Best way to replace linebreaks safely is

yourString.Replace("\r\n","\n") //handling windows linebreaks
.Replace("\r","\n")             //handling mac linebreaks

that should produce a string with only \n (eg linefeed) as linebreaks. this code is usefull to fix mixed linebreaks too.

Use the .Replace() method

Line.Replace("\n", "whatever you want to replace with");

Based on @mark-bayers answer and for cleaner output:

string result = Regex.Replace(ex.Message, @"(\r\n?|\r?\n)+", "replacement text");

It removes \r\n , \n and \r while perefer longer one and simplify multiple occurances to one.

Another option is to create a StringReader over the string in question. On the reader, do .ReadLine() in a loop. Then you have the lines separated, no matter what (consistent or inconsistent) separators they had. With that, you can proceed as you wish; one possibility is to use a StringBuilder and call .AppendLine on it.

The advantage is, you let the framework decide what constitutes a "line break".

This is a very long winded one-liner solution but it is the only one that I had found to work if you cannot use the the special character escapes like "\r" and "\n" and \x0d and \u000D as well as System.Environment.NewLine as parameters to thereplace() method

MyStr.replace(  System.String.Concat( System.Char.ConvertFromUtf32(13).ToString(), System.Char.ConvertFromUtf32(10).ToString() ), ReplacementString  );

This is somewhat offtopic but to get it to work inside Visual Studio's XML .props files, which invoke .NET via the XML properties, I had to dress it up like it is shown below. The Visual Studio XML --> .NET environment just would not accept the special character escapes like "\r" and "\n" and \x0d and \u000D as well as System.Environment.NewLine as parameters to thereplace() method.

$([System.IO.File]::ReadAllText('MyFile.txt').replace( $([System.String]::Concat($([System.Char]::ConvertFromUtf32(13).ToString()),$([System.Char]::ConvertFromUtf32(10).ToString()))),$([System.String]::Concat('^',$([System.Char]::ConvertFromUtf32(13).ToString()),$([System.Char]::ConvertFromUtf32(10).ToString())))))

string s = Regex.Replace(source_string, "\n", "\r\n");

or

string s = Regex.Replace(source_string, "\r\n", "\n");

depending on which way you want to go.

Hopes it helps.

If you want to replace only the newlines:

var input = @"sdfhlu \r\n sdkuidfs\r\ndfgdgfd";
var match = @"[\\ ]+";
var replaceWith = " ";
Console.WriteLine("input: " + input);
var x = Regex.Replace(input.Replace(@"\n", replaceWith).Replace(@"\r", replaceWith), match, replaceWith);
Console.WriteLine("output: " + x);

If you want to replace newlines, tabs and white spaces:

var input = @"sdfhlusdkuidfs\r\ndfgdgfd";
var match = @"[\\s]+";
var replaceWith = "";
Console.WriteLine("input: " + input);
var x = Regex.Replace(input, match, replaceWith);
Console.WriteLine("output: " + x);